[top]
000
FXUS66 KPQR 232118
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
230 PM PDT THU MAY 23 2013
.SYNOPSIS...AN UNSEASONABLY COLD UPPER LEVEL CLOSED LOW WILL REMAIN
OVER THE PAC NW INTO FRI...CONTINUING TO WRAP MOISTURE AROUND MUCH
OF SOUTHWEST WASHINGTON AND NORTHWEST OREGON. THE LOW WILL BEGIN TO
MOVE EAST FRIDAY AND THE PRECIPITATION WILL BREAK UP INTO A MORE
SHOWERY PATTERN. TEMPS WILL WARM A BIT OVER THE WEEKEND...BUT A
CHANCE FOR SHOWERS WILL REMAIN AS WEAK ENERGY MOVES THROUGH. A
COUPLE OF SYSTEMS ARE EXPECTED NEXT WEEK FOR MORE PRECIPITATION
CHANCES.
&&
.SHORT TERM...THE UPPER LOW THAT HAS BEEN OVER THE PACIFIC NW THE
PAST COUPLE OF DAYS WAS STILL OVER WESTERN WA EARLY THU AFTERNOON. A
SHORT WAVE ROTATING AROUND THE LOW WAS PUSHING SW OFF THE N WA
COAST...WITH RADAR SHOWING A LARGE AREA OF RAIN AHEAD OF THE
SHORTWAVE EXTENDING FROM OFF THE WA COAST INTO NW OREGON. AS THIS
WAVE SWINGS AROUND THE LOW AND THROUGH OREGON OVERNIGHT...SHOULD SEE
RAIN INCREASE AGAIN OVER MOST OF THE AREA OVERNIGHT. MODELS WITH
THIS SYSTEM HAVE TENDED TO UNDERESTIMATE RAINFALL AMOUNTS...BUT SEEM
TO HAVE HAVE ADJUSTED SOMEWHAT WITH THE LATEST RUN.
ONCE THIS WAVE MOVES THROUGH...MODELS INDICATING THE THE MAIN PART
OF THE UPPER LOW LIFTS NE TOWARDS SOUTHERN ALBERTA FRI. TO VARYING
DEGREES MODELS SUGGEST A WEAKER SHORTWAVE STILL ON THE BACKSIDE OF
THE LOW FRI...SO WILL LEAVE LIKELY POPS IN THROUGH FRI. AFTER
THAT...A FEW MORE SHORTWAVES STILL EXPECTED SAT INTO SUN...THE MOST
PROMINENT OF WHICH PUSHES INLAND S OF THE FORECAST AREA SUN MORNING.
A MODEST ONSHORE FLOW PERSISTS THROUGH THE PERIOD...NECESSITATING
THE INCLUDION OF POPS THROUGH THE WEEKEND.
.LONG TERM...WESTERLY FLOW ALOFT LIKELY TO BE PERSIST THROUGH THE
EARLY PART OF THE WEEK. THIS WILL KEEP REGION UNDER A PERSISTENT
CHANCE FOR RAIN AS A SERIES OF SHORTWAVES MOVES THROUGH. THE
WESTERLY FLOW OFF THE PACIFIC WILL KEEP TEMPERATURES
MODERATED...LIKELY A LITTLE BELOW SEASONAL AVERAGES. MODELS TEND TO
DIVERGE SOME LATE IN THE WEEK WITH GFS AND CANADIAN CUTTING OFF AN
UPPER LOW OFFSHORE. BOTTOM LINE THOUGH IS FOR A CONTINUATION CHANCE
OF RAIN.
&&
.AVIATION...CIGS HAVE IMPROVED A BIT THIS AFTERNOON...WITH MVFR
MOSTLY ALONG THE COAST AND FAR N INTERIOR AND VFR ELSEWHERE. HOWEVER
AS UPPER LOW OF WASHINGTON COAST DRIFTS A BIT TO THE S AND SW
TONIGHT...SHOULD STILL SEE RA AND MVFR CONDITIONS SPREAD ACROSS THE
REGION THIS EVENING AND TONIGHT. STEADY PRECIP ENDS LATER TONIGHT
BUT MOIST AIR MASS STILL SUPPORTING QUITE A BIT OF MVFR CIGS. WILL
SEE CONDITIONS BECOME VFR OVER MOST AREAS ON FRI WITH SCATTERED
SHOWERS. CASCADES FREQUENTLY OBSCURED THROUGH TONIGHT.
KPDX AND APPROACHES...MIX OF VFR AND MVFR UNTIL 00Z OR 01Z...THEN
WILL HAVE INCREASING MVFR CIGS AS RAIN INCREASES. CIGS IMPROVE A BIT
LATER TONIGHT...BUT STILL HIGHER END MVFR. ROCKEY.
&&
.MARINE...SEAS WERE STILL BOUNCING BETWEEN 9 AND 10 FT...BUT WILL
CONTINUE TO SUBSIDE TONIGHT AND FRI. BROAD LOW PRES STALLED OFF
THE WA COAST AND WEAK PRES GRADIENTS...SO WINDS MOSTLY 15 KT OR
LESS. LOW PRES WILL MOVE INLAND AND WEAKEN FRI AND SAT.
THE NEXT SYSTEM COULD INCREASE WINDS/SEAS LATER SUN OR MON...BUT
STILL UNCERTAINTY ON THE TRACK AND STRENGTH OF THIS SYSTEM. NO
CHANGES FOR NOW...AS LOOKS TO BE DECENT POTENTIAL FOR 20 TO 25 KT
SOUTHERLY WINDS WITH THAT FRONT. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR CONDITIONS UNTIL
6 PM TODAY...AND AGAIN BETWEEN 3 AM AND 8 AM FRI.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
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000
FXUS66 KOTX 231743
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1043 AM PDT Thu May 23 2013
.SYNOPSIS...
Cool, showery weather will continue over the Inland Northwest due
to a lingering upper low. Snow will also be possible over the
mountains. Conditions could moderate a bit by the weekend, as the
low moves out of the area, but it will be replaced by another cool
low sometime early next week.
&&
.DISCUSSION...
A closed low near Seattle this morning will remain west of the
Cascades today. Low level southeast upslope flow and abundant
boundary layer moisture will continue to produce scattered rain
showers along the East Slopes of the Cascades this morning with
isolated showers in the Wenatchee area. Elsewhere shower activity
will hold off until the afternoon hours when the atmosphere
destabilizes. With no organized disturbance to kick off these
showers...they should be mostly isolated in nature...except
scattered Wenatchee area and numerous along the East Slopes with
the low level upslope into these areas and closer proximity to low.
Latest model guidance still points at the East Slopes of the
Cascades, and areas near the Blue Mountains/Camas Prairie as
having the best instability for isolated thunderstorms so this was
maintained in the latest forecast. With persistent cloud cover
expected today for the Wenatchee area, Okanogan Valley, and East
Slopes of the Cascades high temperatures were lowered a bit. Also
lowered Spokane area a few degrees with stratus holding temps down
a bit this morning. JW
&&
.AVIATION...
18Z TAFS: A closed low west of the Cascades will promote showers
over the Inland Northwest today with an increase in activity this
afternoon as the atmosphere destabilizes. Showers will be mainly
focused near the Cascades (closer to the low center), and in the
mountains but with instability over all the area can not completely
rule out a shower for any locations. Instability however will be
greatest near the Cascades and near the Blue Mountains where an
isolated thunderstorm is possible between 21z today through 03z this
evening. Showers should quickly end between 3-5z with the loss of
daytime heating before the next wave brings an increase in clouds
12-18z with the chance for showers increasing again...mainly near
the Cascades and over southeast Washington. CIGS should stay
primarily VFR at the TAF sites. A brief period of BKN020-030
stratocumulus is possible for most TAF sites through 19-20z today.
JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 58 41 60 42 64 45 / 20 20 40 30 20 10
Coeur d`Alene 58 39 59 41 64 43 / 20 20 50 40 20 20
Pullman 60 38 56 40 64 42 / 20 20 50 20 20 20
Lewiston 66 45 63 45 71 49 / 20 10 50 20 20 20
Colville 63 38 67 42 69 43 / 30 30 50 50 40 30
Sandpoint 57 36 62 40 63 40 / 20 20 60 50 30 30
Kellogg 55 39 56 41 60 44 / 20 20 60 50 40 40
Moses Lake 64 43 68 46 72 47 / 20 20 30 20 10 10
Wenatchee 59 44 66 48 69 49 / 40 30 40 20 10 10
Omak 62 38 68 42 69 43 / 30 30 40 30 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
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000
FXUS66 KSEW 231612
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
915 AM PDT THU MAY 23 2013
.SYNOPSIS...A SLOW MOVING COLD UPPER-LEVEL LOW WILL CONTINUE TO
PRODUCE SHOWERS WITH ISOLATED AFTERNOON AND EVENING THUNDERSTORMS
MAINLY OVER THE MOUNTAINS TODAY. THE UPPER LOW WILL WOBBLE AROUND
THE PACIFIC NORTHWEST INTO THE MEMORIAL DAY WEEKEND AS IT SLOWLY
FILLS AND WEAKENS. THE COOL AIR MASS WILL GRADUALLY MODERATE INTO
THE WEEKEND AND SHOWERS WILL GRADUALLY DIMINISH STARTING TONIGHT.
&&
.SHORT TERM...UPPER LEVEL LOW IS SPAWNING WIDESPREAD SHOWERS OVER
THE COAST AND SOUTHERN AREAS WITH SCATTERED SHOWERS ELSEWHERE. THERE
ARE NOTABLY MORE SUN BREAKS TODAY AND HIGH TEMPERATURES SHOULD BE
HIGHER THAN YESTERDAY...MOSTLY 55-60. AS THE LOW PIVOTS EAST THEN
SOUTH WESTERN WASHINGTON WILL BE UNDER AN AREA OF DIVERGENCE ALOFT.
MODELS SHOW NEGATIVE LIFTED INDICES THIS AFTERNOON AND EVENING
MAINLY OVER THE CASCADES BUT ALSO TO SOME EXTENT OVER THE INTERIOR
LOWLANDS. ISOLATED THUNDERSTORMS WITH SMALL HAIL ARE POSSIBLE.
BOTH THE NAM AND THE GFS LIFT THE UPPER LOW NORTHEAST AND FILL IT ON
FRIDAY. THIS WOULD KEEP SCATTERED SHOWERS IN THE FORECAST ESPECIALLY
OVER THE MOUNTAINS. THEN THESE MODELS DAMPEN THE UPPER LOW FURTHER
INTO A BROAD UPPER TROUGH ON SATURDAY AND JUST ZONAL FLOW SUNDAY.
THE EURO IS NOT IN COMPLETE AGREEMENT WITH THESE IDEAS AND KEEPS
SOME SEMBLANCE OF THE UPPER LOW OVER THE AREA THROUGH SUNDAY AND
BEYOND. HOWEVER THE LATEST RUN OF THE EURO HAS GONE SOME WAY TOWARD
THE OTHER MODELS. SO THE FORECAST OF SLOW WARMING AND LOWERING OF
POPS AS TIME PROGRESSES HAS SOME SUPPORT. HIGHS OVER THE INTERIOR
WILL BE IN THE LOW 60S FRIDAY AND THE MID 60S SATURDAY AND SUNDAY.
SOME SORT OF WEAK SYSTEM IS LIKELY MONDAY. BURKE
.LONG TERM...PREVIOUS DISCUSSION...ANOTHER UPPER LEVEL LOW WILL
BRING MORE RAIN TO WESTERN WA ON MEMORIAL DAY. BUT THERE ARE SOME
TIMING DIFFERENCES IN THE MODELS. THE GFS IS THE WETTER MODEL. THE
ECMWF IS SLOWER WITH PRECIP HOLDING OFF UNTIL THE AFTERNOON...AND
MAINLY AFFECTING AREAS SOUTH. SO EXACT DETAILS ARE STILL UNCLEAR AT
THE MOMENT. MODELS KEEP A LONGWAVE TROUGH OVER THE REGION THROUGH
MIDWEEK FOR ADDITIONAL SHOWERS WITH TEMPS NEAR OR SLIGHTLY BELOW
NORMAL. 33
&&
.AVIATION...A DEEP UPPER LOW CENTERED OVER WESTERN WASHINGTON THIS
MORNING WILL REMAIN OVER THE REGION THROUGH TONIGHT. FLOW AT THE
SURFACE AND ALOFT WILL BE GENERALLY LIGHT AND VARIABLE. THE AIR MASS
WILL BE MOIST AND WEAKLY UNSTABLE. SHOWERY PRECIPITATION IS MAINLY
ALONG THE COAST AND IN THE SOUTHWEST INTERIOR THIS MORNING. IT WILL
CONTINUE THROUGH TONIGHT ESPECIALLY OVER THE SOUTHERN TWO-THIRDS OF
THE FORECAST AREA. THERE IS ROUGHLY A 15 PERCENT CHANCE OF
THUNDERSTORMS THIS AFTERNOON AND EVENING.
THERE WAS A WIDE MIX OF CONDITIONS ACROSS THE FORECAST AREA AT 8 AM
-- IFR DUE TO FOG AT KBLI WHERE SKIES WERE CLEAR PART OF THE
NIGHT...LOW-END VFR AND MVFR OVER MOST OF THE PUGET SOUND REGION...
AND MAINLY LOWER CONDITIONS IN SHOWERS ALONG THE COAST AND IN THE
SOUTHWEST INTERIOR. THIS KIND OF VARIABILITY WILL BE THE RULE
THROUGH THE FORECAST PERIOD...MAKING CONFIDENCE IN FORECAST DETAILS
RATHER LOW.
KSEA...SOUTH TO SOUTHWEST WIND 4-8 KT. ROUGHLY A 10 PERCENT CHANCE
OF A THUNDERSTORM THIS AFTERNOON AND EVENING. MCDONNAL
&&
.MARINE...A 1014 MB SURFACE LOW WILL MOVE SLOWLY SOUTHWARD ACROSS
THE WASHINGTON OFFSHORE WATERS TODAY...THEN WEAKEN FURTHER AS IT
MOVES SOUTHEAST INTO OREGON TONIGHT. THIS FEATURE IS PRODUCING SOUTH
TO SOUTHWEST WINDS UP TO 20 KT OVER THE COASTAL WATERS THIS
MORNING...AND THE PLAN TO KEEP WINDS 20 KT OR LESS -- IE BELOW SMALL
CRAFT ADVISORY THRESHOLD -- LOOKS CORRECT.
ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE SATURDAY AND SUNDAY.
SMALL CRAFT ADVISORY WEST WINDS ARE POSSIBLE IN THE CENTRAL STRAIT
OF JUAN DE FUCA AND EAST ENTRANCE STRAIT EACH DAY DURING THE LATE
AFTERNOON AND NIGHTTIME HOURS. A FRONT WILL PROBABLY APPROACH THE
PACIFIC NORTHWEST FROM THE OFFSHORE WATERS MONDAY. MCDONNAL
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...NONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KOTX 231548
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
848 AM PDT Thu May 23 2013
.SYNOPSIS...
Cool, showery weather will continue over the Inland Northwest due
to a lingering upper low. Snow will also be possible over the
mountains. Conditions could moderate a bit by the weekend, as the
low moves out of the area, but it will be replaced by another cool
low sometime early next week.
&&
.DISCUSSION...
A closed low near Seattle this morning will remain west of the
Cascades today. Low level southeast upslope flow and abundant
boundary layer moisture will continue to produce scattered rain
showers along the East Slopes of the Cascades this morning with
isolated showers in the Wenatchee area. Elsewhere shower activity
will hold off until the afternoon hours when the atmosphere
destabilizes. With no organized disturbance to kick off these
showers...they should be mostly isolated in nature...except
scattered Wenatchee area and numerous along the East Slopes with
the low level upslope into these areas and closer proximity to low.
Latest model guidance still points at the East Slopes of the
Cascades, and areas near the Blue Mountains/Camas Prairie as
having the best instability for isolated thunderstorms so this was
maintained in the latest forecast. With persistent cloud cover
expected today for the Wenatchee area, Okanogan Valley, and East
Slopes of the Cascades high temperatures were lowered a bit. Also
lowered Spokane area a few degrees with stratus holding temps down
a bit this morning. JW
&&
.AVIATION...
12Z TAFS: Low level moisture will promote areas of low clouds and
patchy fog this morning around north TAF sites...especially the
KGEG-KCOE corridor. At the same time an unstable upper low
remains in the region. This unusual set-up degrades confidence in
the persistence and timing of low clouds and fog. However expect
IFR conditions through 15-17Z, before mixing mixing and increased
instability with the nearby low helps lift the clouds. The
afternoon will bring an increased threat of rain showers and
perhaps some thunderstorms. The overall best threat will remain
closer to Cascades, near the center of the low, i.e. near KEAT.
The overall threat wanes after dark with the loss of daytime
heating, but a few showers will still remain possible near the
Cascades and Blue Mountains. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 58 41 60 42 64 45 / 20 20 40 30 20 10
Coeur d`Alene 58 39 59 41 64 43 / 20 20 50 40 20 20
Pullman 60 38 56 40 64 42 / 20 20 50 20 20 20
Lewiston 66 45 63 45 71 49 / 20 10 50 20 20 20
Colville 63 38 67 42 69 43 / 30 30 50 50 40 30
Sandpoint 57 36 62 40 63 40 / 20 20 60 50 30 30
Kellogg 55 39 56 41 60 44 / 20 20 60 50 40 40
Moses Lake 64 43 68 46 72 47 / 20 20 30 20 10 10
Wenatchee 59 44 66 48 69 49 / 40 30 40 20 10 10
Omak 62 38 68 42 69 43 / 30 30 40 30 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
000
FXUS66 KPQR 231533
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
832 AM PDT THU MAY 23 2013
.SYNOPSIS...AN UNSEASONABLY COLD UPPER LEVEL CLOSED LOW WILL REMAIN
OVER THE PAC NW TODAY INTO FRI. THE LOW WILL CONTINUE TO WRAP
MOISTURE AROUND MUCH OF SOUTHWEST WASHINGTON AND NORTHWEST OREGON
INTO FRIDAY. THE LOW WILL BEGIN TO MOVE EAST FRIDAY AND THE
PRECIPITATION WILL BREAK UP INTO A MORE SHOWERY PATTERN. TEMPS WILL
WARM A BIT OVER THE WEEKEND... BUT A CHANCE FOR SHOWERS WILL REMAIN
AS WEAK ENERGY MOVES THROUGH. A COUPLE OF SYSTEMS ARE EXPECTED NEXT
WEEK FOR MORE PRECIPITATION CHANCES.
&&
.SHORT TERM...UPPER LOW IS SEEN IN SATELLITE PICTURES OVER WESTERN
WA THIS MORNING. MAIN AREAS OF RAIN AS SEEN IN SATELLITE AND RADAR
IMAGES EXTENDS FROM THE N WILLAMETTE VALLEY NW TO OFF THE WA COAST.
MODELS SUGGEST SOME CONTINUATION OF RAIN IS LIKELY AROUND THE S PART
OF THE LOW...ACROSS THE NORTHERN PARTS OF THE FORECAST AREA TODAY...
BUT FOCUS SHIFTS TO THE SHORTWAVE ROTATING AROUND THE WESTERN
PERIPHERY OF THE LOW. THIS FEATURE SHOULD SPREAD MORE RAIN AROUND TO
THE NW PART OF THE FORECAST AREA THIS AFTERNOON.
REMAINDER OF SHORT TERM DISCUSSION UNCHANGED...
THIS WILL BRING ANOTHER PERIOD OF ENHANCED PRECIPITATION TO MOST OF
THE FCST AREA THROUGH THE NIGHT. THE BACK EDGE OF THE WAVE SHOULD
PASS THROUGH TOWARDS DAYBREAK FRIDAY...WHICH SHOULD BRING AN END TO
THE HEAVIEST PRECIP.
SNOW LEVELS WILL HOVER AROUND 3500 FEET INTO FRIDAY...WITH THE SKI
RESORTS AND HIGHER TERRAIN OF THE CASCADES EXPECTED TO PICK UP
SIGNIFICANT ACCUMULATIONS. THE HIGHER MOUNTAIN PASSES WILL ALSO SEE
SOME SNOW. A COUPLE OF INCHES MAY STICK TO THE ROADS EARLY THIS
MORNING BEFORE ROAD TEMPS RISE ABOVE FREEZING TODAY...MELTING ANY
SNOW THAT ACCUMULATED OVERNIGHT. SNOW MAY STILL TRY TO STICK AT TIMES
LATER TODAY DURING ANY PERIODS OF HEAVIER SNOWFALL. THEN EXPECT SOME
ADDITIONAL LIGHT ACCUMULATIONS EARLY FRI MORNING AS TEMPS COOL AGAIN.
MOUNTAIN CLIMBING AND HIKING UP IN THE MOUNTAINS WILL BE HAZARDOUS
THROUGH FRI. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO HIGHLIGHT
THESE HAZARDS.
THE LOW BEGINS TO WEAKEN AND PUSH EAST OF THE REGION ON FRI. EXPECT
THE PRECIPITATION TO TURN MORE SHOWERY AND BROKEN UP. WE MIGHT SEE A
FEW BREAKS IN THE CLOUDS LATER FRIDAY WHICH COULD LEAD TO A MORE
DIURNAL SIGNAL TO THE SHOWERS FRIDAY AFTERNOON AND EVENING. TEMPS MAY
REACH 60 IN THE INTERIOR LOWLANDS.
MORE LIGHT SHOWERS ARE POSSIBLE ON SAT. MODEL UNCERTAINTIES INCREASE
OVER THE WEEKEND...BUT CONFIDENCE IS HIGH THAT THE PAC NW WILL REMAIN
UNDER THE INFLUENCE OF A TROUGHING PATTERN. HOWEVER...ANY SHOWERS
SHOULD REMAIN ON THE LIGHTER SIDE AND TEMPS WILL CONTINUE TO
MODERATE. MID 60S ARE A GOOD BET FOR MOST VALLEY LOCATIONS. SUNDAY
LOOKS QUITE SIMILAR TO SATURDAY...WITH LIGHT DIURNAL SHOWER CHANCES
EXPECTED TO CONTINUE. PYLE
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS.
THE MODELS SHOW MORE ORGANIZED SYSTEMS ARRIVING ALONG THE WEST COAST
EARLY NEXT WEEK WITH A CHANGE FROM INTERMITTENT SHOWERS TO STEADY
RAIN LIKELY DURING THE BEGINNING OF NEXT WEEK. SNOW LEVELS RISE
SLIGHTLY EARLY NEXT WEEK WITH TEMPERATURES STILL REMAINING SLIGHTLY
BELOW NORMAL. THERE IS STILL NO TENDENCY IN THE LONG RANGE FORECAST
FOR RIDGING TO RETURN TO THE NORTHWEST. KWELSON
&&
.AVIATION...WIDESPREAD MVFR CIGS WITH RAIN ACROSS REGION THIS AM.
BUT BETTER TO S OF KCVO WHERE HAS BEEN DRIER WITH VFR SKIES. NOT
MUCH CHANGE TODAY...AS ANOTHER ROUND OF LIGHT RAIN ARRIVES IN THE N
AND MAINTAINS STATUS QUO THROUGH AT LEAST 03Z. MIX OF VFR AND MVFR
TO S OF KCVO...BUT LIKELY TO SEE INCREASING MVFR CIGS IN THAT AREA
AFT 19Z. MVFR CIGS WILL PERSIST TONIGHT. CASCADES AND HIGHER TERRAIN
WILL BE PERSISTENTLY OBSCURED IN CLOUDS AND LIGHT PRECIP.
KPDX AND APPROACHES...NOT MUCH CHANGE TODAY INTO TONIGHT...WITH
MVFR CIGS AND LIGHT RAIN. MAY HAVE CIGS IMPROVE A BIT TONIGHT...
BUT STILL HIGHER END MVFR. ROCKEY.
&&
.MARINE...SEAS WERE STILL BOUNCING BETWEEN 9 AND 11 FT THIS AM.
EXTENDED SMALL CRAFT ADVISORY OUT UNTIL NOON. BY THEN SEAS WILL
FINALLY BY UNDER 10 FT. WITH BROAD LOW PRES STALLED OFF THE WA
COAST AND WEAK PRES GRADIENTS...WITH WINDS MOSTLY 15 KT OR LESS.
LOW PRES WILL MOVE INLAND AND WEAKEN FRI AND SAT.
THE NEXT SYSTEM COULD INCREASE WINDS/SEAS LATER SUN OR MON...BUT
STILL UNCERTAINTY ON THE TRACK AND STRENGTH OF THIS SYSTEM. NO
CHANGES FOR NOW...AS LOOKS TO BE DECENT POTENTIAL FOR 20 TO 25 KT
SOUTHERLY WINDS WITH THAT FRONT. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL NOON TODAY
ON ALL COASTAL WATERS.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 231355
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
655 AM PDT Thu May 23 2013
.SYNOPSIS...
Cool, showery weather will continue over the Inland Northwest due
to a lingering upper low. Snow will also be possible over the
mountains. Conditions could moderate a bit by the weekend, as the
low moves out of the area, but it will be replaced by another cool
low sometime early next week.
&&
.DISCUSSION...
Update:quick update to remove the freezing warning from the
Palouse, central Panhandle and parts of Nez Perce and Lewis
county. Temperatures are warming up. Also made minor adjustment to
cloud cover. Fog from earlier this morning is also beginning to
wane some but some stratus is holding on in some of the northeast
valleys through the central Panhandle. /J. Cote`
&&
.AVIATION...
12Z TAFS: Low level moisture will promote areas of low clouds and
patchy fog this morning around north TAF sites...especially the
KGEG-KCOE corridor. At the same time an unstable upper low
remains in the region. This unusual set-up degrades confidence in
the persistence and timing of low clouds and fog. However expect
IFR conditions through 15-17Z, before mixing mixing and increased
instability with the nearby low helps lift the clouds. The
afternoon will bring an increased threat of rain showers and
perhaps some thunderstorms. The overall best threat will remain
closer to Cascades, near the center of the low, i.e. near KEAT.
The overall threat wanes after dark with the loss of daytime
heating, but a few showers will still remain possible near the
Cascades and Blue Mountains. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 41 60 42 64 45 / 20 20 40 30 20 10
Coeur d`Alene 59 39 59 41 64 43 / 20 20 50 40 20 20
Pullman 60 38 56 40 64 42 / 20 20 50 20 20 20
Lewiston 66 45 63 45 71 49 / 20 10 50 20 20 20
Colville 63 38 67 42 69 43 / 30 30 50 50 40 30
Sandpoint 57 36 62 40 63 40 / 30 20 60 50 30 30
Kellogg 55 39 56 41 60 44 / 20 20 60 50 40 40
Moses Lake 66 43 68 46 72 47 / 20 20 30 20 10 10
Wenatchee 62 44 66 48 69 49 / 40 30 40 20 10 10
Omak 64 38 68 42 69 43 / 30 30 40 30 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
000
FXUS66 KOTX 231157
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
457 AM PDT Thu May 23 2013
.SYNOPSIS...
Cool, showery weather will continue over the Inland Northwest due
to a lingering upper low. Snow will also be possible over the
mountains. Conditions could moderate a bit by the weekend, as the
low moves out of the area, but it will be replaced by another cool
low sometime early next week.
&&
.DISCUSSION...
Today and tonight: An upper low provides continued hit-and-miss
shower chances and cool temperatures. The low was centered just
south of Seattle this morning. As a shortwave pivots around its
northwest side today, the low is expected to retrograde toward the
mouth of the Columbia River. This will keep the Inland Northwest
in a south to southeasterly flow and in the path of weaker
vorticity maxima. One vort max strings by northeast WA and
northern ID early today and a second slips by the Cascades later
this afternoon and evening. Finally, a third slips across Oregon
toward the Clearwaters late this afternoon and evening too. With
the afternoon heating, models depict increased convective
instability. Agreement on where this instability will lay is
highest over the Cascades to Waterville Plateau and secondarily
across the lower Columbia Basin into the Blue Mountains. One to
two hundred J/kg of CAPE is depicted.
The weak forcing from the passing vort max, coupled with the
south/southeast flow, will support the highest shower chances
across the Cascades, Wenatchee area and Waterville Plateau.
Secondary chances will be found near the Blue Mountains. Given the
unstable nature of the upper trough a slight chance of
thunderstorms will be found here this afternoon and early evening
too. Tertiary chances will be found in northern mountains, largely
due to the orographics. The lowest threat will be of the upper
Columbia Basin through the central Panhandle, including the
Spokane/C`dA area and Palouse as models continue to entrain a fair
amount of dry air into southeast Washington and the Idaho
Panhandle. By tonight waning instability and exiting vorticity max
will diminish the threat of showers throughout much of the region.
The main exceptions will be near the Cascades and near the
Blue Mountains as the main shortwave pivots around from the
northwest to the south side of the low and begins to push swing
across Oregon overnight into Friday morning). /J. Cote`
Friday through Wednesday...Models are in good agreement for Friday
in maintaining a deep upper low pressure over the forecast area.
While the main deformation axis with widespread showers will have
pivoted north and east and be well clear of the region...the
forecast area will reside underneath the destabilizing cold pool
aloft in the center of the upper low. Thus...scattered showers are
a good bet and just about all zones will be susceptible. In
addition...if any sunbreaks occur...which is a distinct
possibility...the prospect for at least isolated thunderstorms
will be very real...again just about anywhere. Temperatures will
remain well below normal through Friday.
From Saturday onward model agreement decreases somewhat...especially
with sub-synoptic details...however the general model consensus is
to weaken or eject the upper low north into Canada and leave a
distinct but weaker troffy pattern over the Northwest US. This is
good news for holiday weekend outdoor planning as it implies that
there are likely to be considerable periods of dry or minimal
shower activity and the main shower activity expected each
afternoon and evening will be concentrated over the mountains
ringing the Columbia Basin. This is not to say that random showers
will not prowl the basin from time to time...just that the
activity will not be as sure a bet as when the upper low was
sitting right over the forecast area.
For the new work week the latest GFS and ECMWF both hint at the
arrival of a new and deeper trough into the region on or about
Tuesday or Wednesday...with the potential for a well defined and
moist frontal surface leading to more widespread showers.
Through this period temperatures will start out well below normal
on Friday and gradually increase day by day to around seasonal
normals by Sunday. /Fugazzi
&&
.AVIATION...
12Z TAFS: Low level moisture will promote areas of low clouds and
patchy fog this morning around north TAF sites...especially the
KGEG-KCOE corridor. At the same time an unstable upper low
remains in the region. This unusual set-up degrades confidence in
the persistence and timing of low clouds and fog. However expect
IFR conditions through 15-17Z, before mixing mixing and increased
instability with the nearby low helps lift the clouds. The
afternoon will bring an increased threat of rain showers and
perhaps some thunderstorms. The overall best threat will remain
closer to Cascades, near the center of the low, i.e. near KEAT.
The overall threat wanes after dark with the loss of daytime
heating, but a few showers will still remain possible near the
Cascades and Blue Mountains. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 41 60 42 64 45 / 20 20 40 30 20 10
Coeur d`Alene 59 39 59 41 64 43 / 20 20 50 40 20 20
Pullman 60 38 56 40 64 42 / 20 20 50 20 20 20
Lewiston 66 45 63 45 71 49 / 20 10 50 20 20 20
Colville 63 38 67 42 69 43 / 30 30 50 50 40 30
Sandpoint 57 36 62 40 63 40 / 30 20 60 50 30 30
Kellogg 55 39 56 41 60 44 / 20 20 60 50 40 40
Moses Lake 66 43 68 46 72 47 / 20 20 30 20 10 10
Wenatchee 62 44 66 48 69 49 / 40 30 40 20 10 10
Omak 64 38 68 42 69 43 / 30 30 40 30 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning until 7 AM PDT this morning for Central Panhandle
Mountains-Idaho Palouse-Lewis and Southern Nez Perce
Counties.
WA...Freeze Warning until 7 AM PDT this morning for Washington
Palouse.
&&
$$
000
FXUS66 KSEW 231026
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 AM PDT THU MAY 23 2013
.SYNOPSIS...A SLOW MOVING COLD UPPER-LEVEL LOW WILL CONTINUE TO
PRODUCE SHOWERS WITH ISOLATED AFTERNOON AND EVENING THUNDERSTORMS
MAINLY OVER THE MOUNTAINS TODAY. THE UPPER LOW WILL WOBBLE AROUND
THE PACIFIC NORTHWEST INTO THE MEMORIAL DAY WEEKEND AS IT SLOWLY
FILLS AND WEAKENS. THE COOL AIR MASS WILL GRADUALLY MODERATE INTO
THE WEEKEND AND SHOWERS WILL GRADUALLY DIMINISH STARTING TONIGHT.
ANOTHER WEATHER SYSTEM IS EXPECTED TO ARRIVE ON MEMORIAL DAY.
&&
.SHORT TERM...EXPECT MORE SHOWERS ACROSS WESTERN WASHINGTON TODAY AS
AN UPPER LEVEL LOW SPINS OVERHEAD. TEMPERATURES WILL REMAIN BELOW
NORMAL ALTHOUGH WE WILL SEE HIGHS A FEW DEGREES WARMER COMPARED TO
YESTERDAY. THE HIGH AT SEATAC WAS ONLY 52 YESTERDAY WHICH SET A
RECORD LOW MAX. THE LOW LEVEL FLOW IS TURNING ONSHORE SO LOOKS LIKE
TEMPS WILL RANGE FROM THE MID 50S TO LOWER 60S. THUNDERSTORMS REMAIN
IN THE FORECAST THIS AFTERNOON AND EVENING WITH THE COLD POOL ALOFT.
TEMPS AT 500 MB ARE AROUND -30 DEG C WITH 850-500MB LAPSE RATES
AROUND -7 C/KM...AND SLIGHTLY NEG LIFTED INDEX. T-STORM COVERAGE IS
ISOLATED AND BEST SHOT OF SEEING ANY STRIKES WILL BE OVER THE
CASCADES. THE SNOW LEVELS ARE AROUND 4000 FT SO PRETTY CHILLY IN THE
MOUNTAINS TODAY. THE MOUNTAINS MAY SEE AN INCH OR TWO OF SNOW...BUT
THE HEAVIEST ACCUMULATIONS WILL BE OVER THE SOUTH WASHINGTON AND
OREGON CASCADES.
THE UPPER LEVEL LOW WILL SLOWLY TRACK INTO EASTERN WA ON FRI...WITH
A FEW MORE WRAP-AROUND SHOWERS AFFECTING WESTERN WA. THE AIR MASS
WILL REMAIN COOL AND UNSTABLE BUT LOOKS LIKE THE T-STORM THREAT WILL
DIMINISH. MODELS SHOW TEMPS MODERATING A BIT WITH HIGHS IN THE LOWER
60S...AND A FEW MORE SUNBREAKS.
THE LOW WILL WEAKEN ON SAT AND SUN AS IT SHIFTS NORTH INTO
BC/ALBERTA...BUT WE STILL HAVE A TROUGH OVER WESTERN WA FOR A
CHANCE OF SHOWERS. 33
.LONG TERM...ANOTHER UPPER LEVEL LOW WILL BRING MORE RAIN TO WESTERN
WA ON MEMORIAL DAY. BUT THERE ARE SOME TIMING DIFFERENCES IN THE
MODELS. THE GFS IS THE WETTER MODEL. THE ECMWF IS SLOWER WITH PRECIP
HOLDING OFF UNTIL THE AFTERNOON...AND MAINLY AFFECTING AREAS SOUTH.
SO EXACT DETAILS ARE STILL UNCLEAR AT THE MOMENT. MODELS KEEP A
LONGWAVE TROUGH OVER THE REGION THROUGH MIDWEEK FOR ADDITIONAL
SHOWERS WITH TEMPS NEAR OR SLIGHTLY BELOW NORMAL. 33
&&
.AVIATION...A STRONG UPPER LEVEL LOW PRESSURE SYSTEM WILL REMAIN
STALLED OVER WA/OREGON THROUGH TONIGHT...THEN START TO SHIFT
EASTWARD FRIDAY. LIGHT SW FLOW ALOFT BECOMING WLY ON FRIDAY. MOIST
AT ALL LEVELS AND SLIGHTLY UNSTABLE. THE RISK FOR AN ISOLATED
THUNDERSTORMS REMAINS LESS THAN 15 PERCENT. SHOWERS THROUGH THIS
EVENING WILL DECREASE AND BECOME MORE SCATTERED TONIGHT AND FRIDAY.
WIDESPREAD MVFR CLOUDS AND PATCHY LOW IFR WHERE MORE STEADY RAIN
DEVELOPS THIS MORNING.
KSEA...SW WIND 4-8 KT. RAIN AT TIMES THIS MORNING...THEN SHOWERS
THIS AFTERNOON AND EVENING. LESS SHOWER ACTIVITY LATER TONIGHT AND
FRIDAY. ROUGHLY A 10 PERCENT CHANCE OF A THUNDERSTORM TODAY THROUGH
THIS EVENING. MVFR CIGS THROUGH MIDDAY WITH IFR CIGS BELOW 1K FT AT
TIMES...LOW VFR OR MVFR CIGS THIS AFTERNOON. DTM
&&
.MARINE...A 1013 MB SURFACE LOW OVER THE SRN WA COASTAL WATERS WILL
MOVE S OVER THE NRN OREGON WATERS BY MIDDAY. THE LOW WILL STALL AND
WEAKEN THE REST OF TODAY...THEN DISSIPATE TONIGHT.
ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE SATURDAY AND SUNDAY.
SMALL CRAFT ADVISORY WINDS ARE POSSIBLE IN THE CENTRAL STRAIT OF
JUAN DE FUCA AND EAST ENTRANCE STRAIT FRIDAY THROUGH SUNDAY DURING
THE LATE AFTERNOON AND NIGHTTIME HOURS. DTM
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KPQR 231021
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
321 AM PDT THU MAY 23 2013
.SYNOPSIS...AN UNSEASONABLY COLD UPPER LEVEL CLOSED LOW REMAINS OVER
THE PAC NW TODAY AND WILL REMAIN NEARLY STATIONARY THROUGH FRI. THE
LOW WILL CONTINUE TO FEED WRAPAROUND MOISTURE ACROSS MUCH OF
SOUTHWEST
WASHINGTON AND NORTHWEST OREGON INTO FRIDAY. THE LOW WILL BEGIN TO
MOVE EAST FRIDAY AND THE PRECIPITATION WILL BREAK UP INTO A MORE
SHOWERY PATTERN. TEMPS WILL WARM A BIT OVER THE WEEKEND... BUT A
CHANCE FOR SHOWERS WILL REMAIN AS WEAK ENERGY MOVES THROUGH. A COUPLE
OF SYSTEMS ARE EXPECTED NEXT WEEK FOR MORE PRECIPITATION CHANCES.
&&
.SHORT TERM...THE UPPER LEVEL CLOSED LOW THAT HAS BEEN NEARLY
STATIONARY OVER THE PAC NW FOR THE PAST FEW DAYS IS CURRENTLY
CENTERED OVER NW WASHINGTON. WRAPAROUND MOISTURE COMBINED WITH A
PIECE OF EMBEDDED SHORTWAVE ENERGY HAS KEPT A BAND OF ENHANCED
PRECIPITATION GOING SINCE YESTERDAY AFTERNOON. MODEL CROSS-SECTIONS
SHOW A FAIRLY DEEP LAYER OF FRONTOGENESIS CONTRIBUTING TO THE
ENHANCED LIFT FROM THE SHORTWAVE. THE PRECIP BAND BECAME MORE FOCUSED
AND HEAVIER DURING THE EVENING AND HAS BEEN FOCUSED ALONG A LINE
ROUGHLY FROM TILLAMOOK FOR THE PDX/VUO METRO AREA AND INTO CLARK
COUNTY ALL THE WAY TO THE S WA CASCADES. RAINFALL TOTALS OVER THE
PAST 6 HRS HAVE TOTAL 3/4 TO 1.5 INCHES THROUGH THIS CORRIDOR.
COMBINING THIS WITH RAINFALL EARLIER IN THE DAY...A FEW SITES HAVE
RECORDED 24 HR RAINFALL TOTALS IN THE 2 TO 3 INCH RANGE.
A DRY SLOT OR BACK EDGE TO THE PRECIP IS VISIBLE ON THE LATEST RADAR
IMAGERY WORKING ITS WAY THROUGH COLUMBIA AND WASHINGTON COUNTY AND
INTO THE PORTLAND METRO AREA. EXPECT THIS SOUTHWARD PUSH TO CONTINUE
OVER THE NEXT FEW HRS...WITH THE HEAVIEST PRECIP FOCUSED THROUGH
YAMHILL AND CLACKAMAS COUNTIES THROUGH THE EARLY MORNING HRS. THE
LATEST FCST MODELS ARE INDICATING THAT THE BOUNDARY SHOULD LOSE SOME
OF ITS ORGANIZATION AND INTENSITY BETWEEN 12Z TO 18Z. BUT EXPECT
LIGHT PRECIPITATION TO CONTINUE ACROSS MOST OF THE REGION TODAY.
ANOTHER SHORTWAVE EMBEDDED IN THE LOW CURRENTLY NEARING VANCOUVER
ISLAND WILL ROTATE S AROUND THE LOW INTO THE REGION LATE THIS
AFTERNOON AND EVENING. THIS WILL BRING ANOTHER PERIOD OF ENHANCED
PRECIPITATION TO MOST OF THE FCST AREA THROUGH THE NIGHT. THE BACK
EDGE OF THE WAVE SHOULD PASS THROUGH TOWARDS DAYBREAK FRIDAY...WHICH
SHOULD BRING AN END TO THE HEAVIEST PRECIP.
SNOW LEVELS WILL HOVER AROUND 3500 FEET INTO FRIDAY...WITH THE SKI
RESORTS AND HIGHER TERRAIN OF THE CASCADES EXPECTED TO PICK UP
SIGNIFICANT ACCUMULATIONS. THE HIGHER MOUNTAIN PASSES WILL ALSO SEE
SOME SNOW. A COUPLE OF INCHES MAY STICK TO THE ROADS EARLY THIS
MORNING BEFORE ROAD TEMPS RISE ABOVE FREEZING TODAY...MELTING ANY
SNOW THAT ACCUMULATED OVERNIGHT. SNOW MAY STILL TRY TO STICK AT TIMES
LATER TODAY DURING ANY PERIODS OF HEAVIER SNOWFALL. THEN EXPECT SOME
ADDITIONAL LIGHT ACCUMULATIONS EARLY FRI MORNING AS TEMPS COOL AGAIN.
MOUNTAIN CLIMBING AND HIKING UP IN THE MOUNTAINS WILL BE HAZARDOUS
THROUGH FRI. A SPECIAL WEATHER STATEMENT HAS BEEN ISSUED TO HIGHLIGHT
THESE HAZARDS.
THE LOW BEGINS TO WEAKEN AND PUSH EAST OF THE REGION ON FRI. EXPECT
THE PRECIPITATION TO TURN MORE SHOWERY AND BROKEN UP. WE MIGHT SEE A
FEW BREAKS IN THE CLOUDS LATER FRIDAY WHICH COULD LEAD TO A MORE
DIURNAL SIGNAL TO THE SHOWERS FRIDAY AFTERNOON AND EVENING. TEMPS MAY
REACH 60 IN THE INTERIOR LOWLANDS.
MORE LIGHT SHOWERS ARE POSSIBLE ON SAT. MODEL UNCERTAINTIES INCREASE
OVER THE WEEKEND...BUT CONFIDENCE IS HIGH THAT THE PAC NW WILL REMAIN
UNDER THE INFLUENCE OF A TROUGHING PATTERN. HOWEVER...ANY SHOWERS
SHOULD REMAIN ON THE LIGHTER SIDE AND TEMPS WILL CONTINUE TO
MODERATE. MID 60S ARE A GOOD BET FOR MOST VALLEY LOCATIONS. SUNDAY
LOOKS QUITE SIMILAR TO SATURDAY...WITH LIGHT DIURNAL SHOWER CHANCES
EXPECTED TO CONTINUE. PYLE
.LONG TERM... THE MODELS SHOW MORE ORGANIZED SYSTEMS ARRIVING ALONG
THE WEST COAST EARLY NEXT WEEK WITH A CHANGE FROM INTERMITTENT
SHOWERS TO STEADY RAIN LIKELY DURING THE BEGINNING OF NEXT WEEK. SNOW
LEVELS RISE SLIGHTLY EARLY NEXT WEEK WITH TEMPERATURES STILL
REMAINING SLIGHTLY BELOW NORMAL. THERE IS STILL NO TENDENCY IN THE
LONG RANGE FORECAST FOR RIDGING TO RETURN TO THE NORTHWEST. KWELSON
&&
.AVIATION...UPPER LEVEL LOW OVER REGION CONTINUES TO GENERATE
AREAS OF RAIN. AREAS MOST LIKELY TO SEE IFR WILL BE THE COASTAL
AREAS WITH AREAS OF RAIN AND FOG. MVFR/VFR CIGS INLAND WITH AREAS
OF RAIN...LOCALLY HEAVY AT TIMES. MOUNTAINS WILL GENERALLY BE
OBSCURED THROUGH THE DAY. WITH A SLIGHTLY UNSTABLE AIR MASS WE
CANNOT RULE OUT A STRAY THUNDERSTORM TODAY...BUT THE BETTER CHANCE
WILL BE NORTH AND EAST OF OUR FORECAST AREA.
KPDX AND APPROACHES...HEAVIEST RAIN FROM OVERNIGHT APPEARS TO HAVE
SHIFTED SOUTHEAST OF KPDX FOR THE TIME BEING. EXPECT MVFR WITH
POSSIBLE BREAKS INTO VFR THIS MORNING WITH RAIN CONTINUING EAST
AND SOUTH OF THE METRO AREA. MIX OF MVFR/VFR TO CONTINUE INTO THIS
EVENING WITH OCCASIONAL RAIN AND LIGHT-MODERATE S-SE FLOW. WEAGLE
&&
.MARINE...HAD TO HOLD ON THE SMALL CRAFT ADVISORY FOR SEAS A FEW
MORE HOURS AS BUOYS ARE RUNNING 10-11 FT THIS MORNING. SUSPECT BY
7 AM MOST OF THEM SHOULD BE BELOW 10 FT AND WILL BE ABLE TO DROP
THE SCA AT THAT POINT. WITH BROAD LOW PRESSURE STALLED OFF THE WA
COAST AND WEAK PRESSURE GRADIENTS...WINDS ARE GENERALLY LIGHT
ACROSS THE WATERS. A DISTURBANCE ROTATING AROUND THIS SYSTEM WILL
PROBABLY BRING SOME S WIND GUSTS TO 20 KT LATER THIS AFTERNOON AND
EVENING.
LOW PRESSURE WILL MOVE INLAND AND WEAKEN FRI/SAT...WITH LIGHT
WINDS AND DIMINISHING SEAS GOING INTO THE WEEKEND. THE NEXT SYSTEM
COULD INCREASE WINDS/SEAS LATE SUN OR MON...BUT THERE IS STILL
SOME UNCERTAINTY ON THE TRACK AND STRENGTH OF THIS SYSTEM.
MORNING EBBS WILL BE RATHER STRONG THE NEXT SEVERAL DAYS DUE TO
THE FULL MOON. THIS WILL LIKELY CREATE ROUGH BAR CONDITIONS DURING
THE STRONGER MORNING EBBS. WEAGLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 7 AM PDT THIS
MORNING FOR COASTAL WATERS FROM CAPE SHOALWATER TO FLORENCE
OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 6 AM
EARLY THIS MORNING.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 230924
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
224 AM PDT Thu May 23 2013
.SYNOPSIS...
Cool, showery weather will continue over the Inland Northwest due
to a lingering upper low. Snow will also be possible over the
mountains. Conditions could moderate a bit by the weekend, as the
low moves out of the area, but it will be replaced by another cool
low sometime early next week.
&&
.DISCUSSION...
Today and tonight: An upper low provides continued hit-and-miss
shower chances and cool temperatures. The low was centered just
south of Seattle this morning. As a shortwave pivots around its
northwest side today, the low is expected to retrograde toward the
mouth of the Columbia River. This will keep the Inland Northwest
in a south to southeasterly flow and in the path of weaker
vorticity maxima. One vort max strings by northeast WA and
northern ID early today and a second slips by the Cascades later
this afternoon and evening. Finally, a third slips across Oregon
toward the Clearwaters late this afternoon and evening too. With
the afternoon heating, models depict increased convective
instability. Agreement on where this instability will lay is
highest over the Cascades to Waterville Plateau and secondarily
across the lower Columbia Basin into the Blue Mountains. One to
two hundred J/kg of CAPE is depicted.
The weak forcing from the passing vort max, coupled with the
south/southeast flow, will support the highest shower chances
across the Cascades, Wenatchee area and Waterville Plateau.
Secondary chances will be found near the Blue Mountains. Given the
unstable nature of the upper trough a slight chance of
thunderstorms will be found here this afternoon and early evening
too. Tertiary chances will be found in northern mountains, largely
due to the orographics. The lowest threat will be of the upper
Columbia Basin through the central Panhandle, including the
Spokane/C`dA area and Palouse as models continue to entrain a fair
amount of dry air into southeast Washington and the Idaho
Panhandle. By tonight waning instability and exiting vorticity max
will diminish the threat of showers throughout much of the region.
The main exceptions will be near the Cascades and near the
Blue Mountains as the main shortwave pivots around from the
northwest to the south side of the low and begins to push swing
across Oregon overnight into Friday morning). /J. Cote`
Friday through Wednesday...Models are in good agreement for Friday
in maintaining a deep upper low pressure over the forecast area.
While the main deformation axis with widespread showers will have
pivoted north and east and be well clear of the region...the
forecast area will reside underneath the destabilizing cold pool
aloft in the center of the upper low. Thus...scattered showers are
a good bet and just about all zones will be susceptible. In
addition...if any sunbreaks occur...which is a distinct
possibility...the prospect for at least isolated thunderstorms
will be very real...again just about anywhere. Temperatures will
remain well below normal through Friday.
From Saturday onward model agreement decreases somewhat...especially
with sub-synoptic details...however the general model consensus is
to weaken or eject the upper low north into Canada and leave a
distinct but weaker troffy pattern over the Northwest US. This is
good news for holiday weekend outdoor planning as it implies that
there are likely to be considerable periods of dry or minimal
shower activity and the main shower activity expected each
afternoon and evening will be concentrated over the mountains
ringing the Columbia Basin. This is not to say that random showers
will not prowl the basin from time to time...just that the
activity will not be as sure a bet as when the upper low was
sitting right over the forecast area.
For the new work week the latest GFS and ECMWF both hint at the
arrival of a new and deeper trough into the region on or about
Tuesday or Wednesday...with the potential for a well defined and
moist frontal surface leading to more widespread showers.
Through this period temperatures will start out well below normal
on Friday and gradually increase day by day to around seasonal
normals by Sunday. /Fugazzi
&&
.AVIATION...
06Z TAFS: An upper level low pressure area centered in the vicinity
of the aviation area will keep the threat for -shra vcnty KEAT and
KMWH through much of the night and Thur morning. Aftn heating will
promote light but widely sct -shra across the region for just about
any location. Some showers may produce MVFR ceilings at times.
Additionally some late night and early morning fog could produce
brief IFR/LIFR visibilities with KSFF/KLWS carrying the highest
threat for fog formation. Patchy frost will be possible near KPUW
and KDEW. All terminals are expected to receive a break from pcpn
and VFR skies aft 02z. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 60 41 60 42 64 45 / 20 20 40 30 20 10
Coeur d`Alene 59 39 59 41 64 43 / 20 20 50 40 20 20
Pullman 60 38 56 40 64 42 / 20 20 50 20 20 20
Lewiston 66 45 63 45 71 49 / 20 10 50 20 20 20
Colville 63 38 67 42 69 43 / 30 30 50 50 40 30
Sandpoint 57 36 62 40 63 40 / 30 20 60 50 30 30
Kellogg 55 39 56 41 60 44 / 20 20 60 50 40 40
Moses Lake 66 43 68 46 72 47 / 20 20 30 20 10 10
Wenatchee 62 44 66 48 69 49 / 40 30 40 20 10 10
Omak 64 38 68 42 69 43 / 30 30 40 30 30 20
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning until 7 AM PDT this morning for Central Panhandle
Mountains-Idaho Palouse-Lewis and Southern Nez Perce
Counties.
WA...Freeze Warning until 7 AM PDT this morning for Washington
Palouse.
&&
$$
000
FXUS66 KOTX 230539
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1045 PM PDT Wed May 22 2013
.SYNOPSIS...
a cool and wet period awaits the Inland Northwest care of a cold
upper level low. Occasional showers are expected each day through
the end of the week with cooler than normal temperatures. snow
will also be possible over the mountains. Conditions could
moderate a bit by the weekend as the low moves out of the area
but it will be replaced by another cool low sometime early next week.
&&
.DISCUSSION...
Second update for this evening: A band of nearly stationary light
to locally moderate precipitation remains in place across
Boundary...northern Pend Oreille...and northern Stevens Counties.
Following some calls to the counties...there is very little issues
regarding flooding from the 1-3 inches of rainfall over the last 2
days. Consequently, we have allowed the flood advisory to run its
course and allowed the product to expire as this band will finally
begin to drift north this evening as a dry slot now into
southeastern WA punches northward.
There are still some nuisance showers that were tied to the
afternoon instability and some weak midlevel forcing that will be
around for the next few hours. The most organized activity is a
along a line extending from Omak to Coeur D Alene. A second
cluster near Walla Walla will drift north into southern Adams and
western Whitman Counties within the hour. Lastly, isolated showers
continue to blossom over the western Columbia Basin and drift west
into the East Slopes. Each of these features will be capable of
brief heavy downpours and B-B size hail but should gradually
dissipate with the loss of daytime heating.
The key word is "should"...given the -30C cold pool aloft and
perhaps another midlevel circulation (vort max)...it is not a high
confidence forecast that the region will showers will
cease...especially over the East Slopes and far western Basin
within the proximity of the parent upper-low and we will maintain
a slight chance to chance wording.
As for temperatures...this is a tough forecast to say the least.
Most locations are carrying dewpoints that would keep temperatures
slightly above freezing tonight but given the clearing moving in
from the southeast under the dry slot...it will be a battle during
radiational cooling between going below freezing and formation of
fog. Several isolated locations like Winchester, Davenport,
Republic, Deer Park, and Priest Lake should reach freezing
overnight but there is low confidence that this will be widespread
enough throughout the zone to include in the freeze warning.
It still looks possible for the ID/WA Palouse so will maintain the
warning and will include the valleys of IDZ004 (Central Panhandle
Mtns) and Camas Prairie which received much less precipitation
throughout the day and will experience a great deal of clearing
and light winds overnight and have the best shot for a hard freeze
(25-29F). Locations like Bonners Ferry which fell to 32F under
moderate snow today have rebounded back around 36F and should
quickly fog in tonight as the precipitation ends. /sb
&&
.AVIATION...
06Z TAFS: An upper level low pressure area centered in the vicinity
of the aviation area will keep the threat for -shra vcnty KEAT and
KMWH through much of the night and Thur morning. Aftn heating will
promote light but widely sct -shra across the region for just about
any location. Some showers may produce MVFR ceilings at times.
Additionally some late night and early morning fog could produce
brief IFR/LIFR visibilities with KSFF/KLWS carrying the highest
threat for fog formation. Patchy frost will be possible near KPUW
and KDEW. All terminals are expected to receive a break from pcpn
and VFR skies aft 02z. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 60 41 60 42 64 / 30 20 20 40 30 30
Coeur d`Alene 35 59 37 60 40 64 / 70 20 20 50 40 30
Pullman 32 59 37 57 40 64 / 20 20 20 50 20 30
Lewiston 36 66 44 64 45 71 / 20 20 10 50 20 30
Colville 35 63 37 68 41 69 / 70 30 30 50 50 40
Sandpoint 34 58 35 62 39 64 / 80 30 20 60 50 40
Kellogg 29 55 37 56 41 61 / 70 30 30 60 50 40
Moses Lake 39 66 41 69 45 72 / 20 20 20 30 20 10
Wenatchee 41 63 44 66 47 69 / 60 40 30 40 20 20
Omak 35 65 37 68 42 69 / 50 30 30 40 30 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning from 2 AM to 7 AM PDT Thursday for Central
Panhandle Mountains-Idaho Palouse-Lewis and Southern Nez
Perce Counties.
WA...Freeze Warning from 2 AM to 7 AM PDT Thursday for Washington
Palouse.
&&
$$
000
FXUS66 KOTX 230459
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
959 PM PDT Wed May 22 2013
.SYNOPSIS...
a cool and wet period awaits the Inland Northwest care of a cold
upper level low. Occasional showers are expected each day through
the end of the week with cooler than normal temperatures. snow
will also be possible over the mountains. Conditions could
moderate a bit by the weekend as the low moves out of the area
but it will be replaced by another cool low sometime early next week.
&&
.DISCUSSION...
Second update for this evening: A band of nearly stationary light
to locally moderate precipitation remains in place across
Boundary...northern Pend Oreille...and northern Stevens Counties.
Following some calls to the counties...there is very little issues
regarding flooding from the 1-3 inches of rainfall over the last 2
days. Consequently, we have allowed the flood advisory to run its
course and allowed the product to expire as this band will finally
begin to drift north this evening as a dry slot now into
southeastern WA punches northward.
There are still some nuisance showers that were tied to the
afternoon instability and some weak midlevel forcing that will be
around for the next few hours. The most organized activity is a
along a line extending from Omak to Coeur D Alene. A second
cluster near Walla Walla will drift north into southern Adams and
western Whitman Counties within the hour. Lastly, isolated showers
continue to blossom over the western Columbia Basin and drift west
into the East Slopes. Each of these features will be capable of
brief heavy downpours and B-B size hail but should gradually
dissipate with the loss of daytime heating.
The key word is "should"...given the -30C cold pool aloft and
perhaps another midlevel circulation (vort max)...it is not a high
confidence forecast that the region will showers will
cease...especially over the East Slopes and far western Basin
within the proximity of the parent upper-low and we will maintain
a slight chance to chance wording.
As for temperatures...this is a tough forecast to say the least.
Most locations are carrying dewpoints that would keep temperatures
slightly above freezing tonight but given the clearing moving in
from the southeast under the dry slot...it will be a battle during
radiational cooling between going below freezing and formation of
fog. Several isolated locations like Winchester, Davenport,
Republic, Deer Park, and Priest Lake should reach freezing
overnight but there is low confidence that this will be widespread
enough throughout the zone to include in the freeze warning.
It still looks possible for the ID/WA Palouse so will maintain the
warning and will include the valleys of IDZ004 (Central Panhandle
Mtns) and Camas Prairie which received much less precipitation
throughout the day and will experience a great deal of clearing
and light winds overnight and have the best shot for a hard freeze
(25-29F). Locations like Bonners Ferry which fell to 32F under
moderate snow today have rebounded back around 36F and should
quickly fog in tonight as the precipitation ends. /sb
&&
.AVIATION...
00Z TAFS: An upper level low pressure area centered in the vicinity
of the aviation area allows for a cluttered forecast of primarily
showers at various times, either surface based or the elevated
forced type in the forecast for most of the time interval through
00Z Friday. These showers may produce MVFR ceilings at times.
Additionally some late night and early morning fog near rivers and
northern valleys could produce brief MVFR visibilities along with
some frost as temperatures drop below freezing for a brief spell
near KPUW, KDEW...and other more favorable aviation locations.
Additionally a very small potential for thunder exists near
Cascades and vicinity KLWS and portions of North Idaho Panhandle.
/Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 60 41 60 42 64 / 30 20 20 40 30 30
Coeur d`Alene 35 59 37 60 40 64 / 70 20 20 50 40 30
Pullman 32 59 37 57 40 64 / 20 20 20 50 20 30
Lewiston 36 66 44 64 45 71 / 20 20 10 50 20 30
Colville 35 63 37 68 41 69 / 70 30 30 50 50 40
Sandpoint 34 58 35 62 39 64 / 80 30 20 60 50 40
Kellogg 29 55 37 56 41 61 / 70 30 30 60 50 40
Moses Lake 39 66 41 69 45 72 / 20 20 20 30 20 10
Wenatchee 41 63 44 66 47 69 / 60 40 30 40 20 20
Omak 35 65 37 68 42 69 / 50 30 30 40 30 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning from 2 AM to 7 AM PDT Thursday for Central
Panhandle Mountains-Idaho Palouse-Lewis and Southern Nez
Perce Counties.
WA...Freeze Warning from 2 AM to 7 AM PDT Thursday for Washington
Palouse.
&&
$$
000
FXUS66 KPQR 230413
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
913 PM PDT WED MAY 22 2013
.SYNOPSIS...AN UNSEASONABLY COLD LOW PRESSURE SYSTEM WAS OVER THE
PACIFIC NORTHWEST AND WILL MOVE LITTLE INTO FRIDAY. THIS LOW WILL
CONTINUE TO FEED WRAPAROUND MOISTURE ACROSS MUCH OF SOUTHWEST
WASHINGTON AND NORTHWEST OREGON INTO FRIDAY. THE LOW WILL BEGIN TO
MOVE EAST FRIDAY AND THE PRECIPITATION WILL BREAK UP INTO A MORE
SHOWERY PATTERN. SOME CHANCE FOR SHOWERS WILL REMAIN INTO THE WEEKEND
AS WEAK ENERGY MOVES THROUGH. A COUPLE OF SYSTEMS ARE EXPECTED NEXT
WEEK FOR AN INCREASED LIKELIHOOD OF PRECIPITATION AGAIN.
&&
.SHORT TERM...AN UPPER LOW WAS SPINNING...CENTERED IN WESTERN OR EVEN
SOUTHWEST WASHINGTON THIS EVENING. THE LOW IS FORECAST TO MOVE LITTLE
INTO EARLY FRIDAY AS ENERGY AND MOISTURE CONTINUES TO WRAP AROUND THE
LOW AND ACROSS MUCH OF SOUTHWEST WASHINGTON AND NORTHWEST OREGON AT
TIMES. THERE IS SOME INDICATION OF A SLIGHT BREAK OR EASE UP IN THE
PRECIPITATION LATER TONIGHT AND EARLY THURSDAY BUT TIMING AND
CONFIDENCE NOT HIGH SO DID NOT TRY AND ADD TOO MUCH DETAIL IN THE
GRIDS AND THE FORECAST FOR THAT. THERE IS ONE MORE GOOD SHORT WAVE
SWINGING AROUND THE SOUTHERN PERIPHERY OF THE LOW AND ACROSS OUR
AREA LATER THURSDAY AND THURSDAY NIGHT...AFTER WHICH THE
PRECIPITATION SHOULD BECOME MORE SHOWERY AND INTERMITTENT AND BROKEN
UP.
PRIOR TO THAT...IT SHOULD BE MORE WET THAN NOT IN MUCH OF OUR AREA.
HAVE BOOSTED POPS CONSIDERABLY TO REFLECT BOTH THE CURRENT
PRECIPITATION AND THE EXPECTED CONTINUATION INTO EARLY FRIDAY. HAVE
EASED TEMPS DOWN FOR THURSDAY AS IT WILL TEND TO BE PRETTY CLOUDY
AND HAVE TROUBLE WARMING UP LIKE TODAY...THOUGH DO EXPECT IT A BIT
WARMER. SNOW LEVELS WILL HOVER AROUND 3500 FEET INTO FRIDAY...AND
SNOW AMOUNTS COULD EXCEED 6 INCHES IN THE HIGHER ELEVATIONS SUCH AS
THE SKI RESORTS AND THE MOUNTAIN PEAKS...WITH MUCH LESS ACCUMULATION
ACROSS THE PASSES WHERE ROADS ARE ON THE WARM SIDE. MOUNTAIN
CLIMBING AND HIKING UP IN THE MOUNTAINS WILL BE HAZARDOUS. HAVE
ISSUED A SPECIAL WEATHER STATEMENT TO HIGHLIGHT THESE HAZARDS.
THE LOW DRIFTS MORE INTO CENTRAL AND EASTERN WASHINGTON ON FRIDAY...
AND THE PRECIPITATION TURNS MORE SHOWERY AND BROKEN UP. WE MIGHT SEE
A FEW BREAKS IN THE CLOUDS LATER FRIDAY WHICH COULD LEAD TO A MORE
DIURNAL SIGNAL TO THE SHOWERS FRIDAY AFTERNOON AND EVENING. TEMPS
MAY GET CLOSER TO 60 FINALLY ON FRIDAY.
THE LOW REMAINS NEARBY ON SATURDAY...AND AS A RESULT THERE WILL
REMAIN A CHANCE FOR SOME SHOWERS...ESPECIALLY IN THE AFTERNOON AND
EVENING. UNFORTUNATELY...THERE ARE BIG DIFFERENCES IN THE GFS MODEL
AND THE ECMWF MODEL FOR SATURDAY. THE ECMWF MODEL PARKS ANOTHER LOW
OFF THE WASHINGTON COAST LATER SATURDAY AND OVER THE REMAINDER OF
THE WEEKEND...WHILE THE GFS JUST DRIFTS WEAKER PIECES OF ENERGY
ACROSS THE AREA. WILL STAY WITH THE CURRENT MIDDLE OF THE ROAD
FORECAST FOR NOW. TOLLESON
.LONG TERM...SATURDAY EVENING THROUGH TUESDAY...SEVERAL SHORTWAVE
SYSTEMS ROTATE THROUGH A BROAD UPPER LEVEL LOW OVER THE NORTHEAST
PACIFIC AND WEST COAST. THE UPPER LOW LINGERS ACROSS THE REGION
THROUGH THE WEEKEND...KEEPING PERIODS OF SHOWERS AND BRIEF CLOUD
BREAKS IN THE FORECAST THROUGH THE WEEKEND. THE MODELS SHOW MORE
ORGANIZED SYSTEMS ARRIVING ALONG THE WEST COAST EARLY NEXT WEEK WITH
A CHANGE FROM INTERMITTENT SHOWERS TO STEADY RAIN LIKELY DURING THE
BEGINNING OF NEXT WEEK. SNOW LEVELS RISE SLIGHTLY EARLY NEXT WEEK
WITH TEMPERATURES STILL REMAINING SLIGHTLY BELOW NORMAL. THERE IS
STILL NO TENDENCY IN THE LONG RANGE FORECAST FOR RIDGING TO RETURN TO
THE NORTHWEST. KWELSON
&&
.AVIATION...UPPER LOW OVER REGION WILL MOVE LITTLE TONIGHT. EXPECT
LIGHT RAIN TO CONTINUE TONIGHT THROUGH AT LEAST THURSDAY MORNING WITH
A MIX OF MVFR AND VFR. ONE MODEL SHOWS DECENT LIFT DEVELOPING OVER
THE CENTRAL AND SOUTH PORTIONS...ROUGHLY AREAS SOUTH OF SALEM...LATER
TONIGHT INTO EARLY THU MORNING. THIS COULD BRING IFR CONDITIONS TO
THESE AREAS. HOWEVER...CONFIDENCE OF IFR CONDITIONS OCCURRING IS NOT
VERY HIGH BUT WILL HAVE TO WATCH OUT FOR.
KPDX AND APPROACHES...MIX OF VFR WITH OCCASIONAL VFR TO START BUT
PROBABLY TREND TOWARD MVFR AFTER 09Z...THEN TO LOW END VFR WITH
OCCASIONAL MVFR AFTER 17Z THU.
&&
.MARINE...LITTLE CHANGE. W TO NW WINDS CONTINUE...GENERALLY 10 TO 15
KT. WINDS REMAIN 15 KT OR LESS THROUGH SUN AS PRES GRADIENTS NOT ALL
THAT STRONG. ANOTHER FRONT WILL ARRIVE EARLY NEXT WEEK...WITH S TO SW
WINDS UP TO 20 KT AGAIN.
SEAS GENERALLY 10 TO 13 FT TONIGHT...BUT WILL GRADUALLY SUBSIDE LATER
TONIGHT AND THU...DROPPING BELOW 10 FT LATE TONIGHT. SEAS WILL
CONTINUE TO GRADUALLY SUBSIDE THROUGH SUN. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL MIDNIGHT PDT
TONIGHT FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
6 AM PDT THURSDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 230021
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
521 PM PDT Wed May 22 2013
.SYNOPSIS...
a cool and wet period awaits the Inland Northwest care of a cold
upper level low. Occasional showers are expected each day through
the end of the week with cooler than normal temperatures. snow
will also be possible over the mountains. Conditions could
moderate a bit by the weekend as the low moves out of the area
but it will be replaced by another cool low sometime early next week.
&&
.DISCUSSION...
Evening update: We have lowered snow levels and added some light
snow accumulations for the far northern portions of the Idaho
Panhandle...mostly over Boundary County where moderate to heavy
precipitation continues to fall and is driving down snow levels to
elevations as low as 1800 ft. A spotter from Moyie at an elevation
of 2300` has reported one inch of snow with this activity. Most
CAMS from the area do not show accumulations on roadways so will
hold off on any winter weather highlights.
We have also increased pops and added isolated thunderstorms
across southeastern WA and lower portions of the Columbia Basin.
Breaks in the cloud cover coupled with the -30C cold pool under
the upper-low has resulted in widely scattered showers and a few
thunderstorms. At this time the main t-storm activity was over the
Pomeroy area and this may need to be expanded to the west and
north and will see how trends are the next hour before making
additional changes. /sb
&&
.AVIATION...
00Z TAFS: An upper level low pressure area centered in the vicinity
of the aviation area allows for a cluttered forecast of primarily
showers at various times, either surface based or the elevated
forced type in the forecast for most of the time interval through
00Z Friday. These showers may produce MVFR ceilings at times.
Additionally some late night and early morning fog near rivers and
northern valleys could produce brief MVFR visibilities along with
some frost as temperatures drop below freezing for a brief spell
near KPUW, KDEW...and other more favorable aviation locations.
Additionally a very small potential for thunder exists near
Cascades and vicinity KLWS and portions of North Idaho Panhandle.
/Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 60 41 60 42 64 / 20 20 20 40 30 30
Coeur d`Alene 35 59 37 60 40 64 / 20 20 20 40 40 30
Pullman 32 59 37 57 40 64 / 30 20 20 40 20 30
Lewiston 38 66 44 64 45 71 / 40 20 10 40 20 30
Colville 35 63 37 68 41 69 / 70 30 30 50 40 40
Sandpoint 34 58 35 62 39 64 / 80 30 20 50 50 40
Kellogg 34 55 37 56 41 61 / 40 30 30 50 50 40
Moses Lake 39 66 41 69 45 72 / 40 20 20 30 20 10
Wenatchee 41 63 44 66 47 69 / 60 40 30 30 20 20
Omak 35 65 37 68 42 69 / 60 30 30 40 30 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning from 2 AM to 7 AM PDT Thursday for Idaho Palouse.
WA...Freeze Warning from 2 AM to 7 AM PDT Thursday for Washington
Palouse.
&&
$$
000
FXUS66 KOTX 222333
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
426 PM PDT Wed May 22 2013
.SYNOPSIS...
a cool and wet period awaits the Inland Northwest care of a cold
upper level low. Occasional showers are expected each day through
the end of the week with cooler than normal temperatures. snow
will also be possible over the mountains. Conditions could
moderate a bit by the weekend as the low moves out of the area
but it will be replaced by another cool low sometime early next week.
&&
.DISCUSSION...
Tonight...Large closed low centered near Yakima this evening will
move northwest towards Seattle overnight. Models show the theta e
ridge axis which has brought heavy rain over the North Idaho
Panhandle and north Pend Oreille county shifting east into western
Montana this evening. A flood advisory remains in effect through
this evening for this area. The closed low position tonight will
result in south-southeast flow over Central and Eastern
Washington and North Idaho with showers rotating around the low.
LAPS data from this afternoon also has CAPE values of around 200
J/KG from Wenatchee through Hanford and the Blue Mountains which
could spark a stray thunderstorm. All models show a wedge of drier
air coming up from the south tonight which should dry most areas
out once evening showers die off with the loss of daytime heating.
However closer to the Cascades showers may persist overnight given
close proximity to low center.
With the drier air skies will have an opportunity to become mostly
clear or partly cloudy for Eastern Washington overnight. This
combined with a cool start with afternoon temperatures only in the
mid 40s over most areas will result in a cool night. Freezing
temperatures are expected for most locations on the Palouse and a
freeze warning has been issued. A tougher call for the northern
valleys where abundant boundary layer moisture may allow for more
fog or stratus to develop which would keep lows near or slightly
below freezing. With lower confidence opted to not include the
northern valleys, but colder spots like Republic and Deer Park
will have a good chance of reaching 30-32 degrees F. JW
.Thursday through Saturday...Cold upper level low will remain
the dominant feature through this period. Model solutions are
exhibiting very good agreement with the movement of the low and
the placement of the associated deformation band of precipitation.
The current deformation band which is responsible for the
widespread band of precipitation extending from NE Washington into
the central Panhandle...is expected to track E-NE overnight and
and move into NW Montana by late-morning or early afternoon. Drier
and more stable air is expected to move in its wake which will
likely bring a brief drying trend across much of the Inland NW at
least through the morning. The atmosphere is expected to
destabilize in the afternoon due to diurnal heating...and
scattered showers could develop over the eastern half of the
forecast area. Farther west...the presence of the low near the
mouth of the Columbia will result in weak upslope easterly flow
into the Cascades and keep more persistent shower activity fixed
over that region. Temperatures should moderate quite a bit
compared to today as a bit more sunshine is expected with the core
of the upper level low shifting the coldest air to our west.
By Thursday night into early Friday the low is expected to wobble
into central Oregon before heading north-northeast. This should
result in drying conditions for most locations. By Friday
afternoon...the models continue to exhibit great consistency by
showing the upper level low will wandering into NE Oregon with the
atmosphere over the Inland NW exhibiting a rapid destabilization.
Showers will likely become plentiful as model CAPE values climb
into the 250-500 j/kg range with no convective CAP. Given the
southerly mid-level flow...the most abundant activity will cluster
along the northern forecast zones adjacent to the Canadian border.
Thunderstorms look like a possibility given the stability
parameters...however the lack of strong ascent aloft the coverage
will be underwhelming.
For Saturday...the low will meander back west of the Cascades...
with the best chances of precipitation focusing over the northern
and western portions of the forecast area...near the Canadian
border and Cascades. Once again the instability parameters suggest
a small chance of thunderstorms...however most of the upper level
ascent will remain focused west of the Cascades. Temperatures will
continue to moderate through the period with highs climbing into
the mid 60s to lower 70s for most valley locations. fx
Saturday night through Wednesday...Long-wave trof continues to
influence the Western United States through this time
interval...therefore this interval remains marked with below
normal temperatures...lower than usual snow levels at times...and
moderate pops and amounts of precipitation at times. The flow
does become westerly enough and void of disturbances to allow for
some intervals of drying between shortwave passages but as far as
shortwave features traversing through there are just enough timing
differences in passing each one through (and there appears to be
about four or more) that there isn`t enough confidence to modify
any timing of each feature in the forecast...so the end result
syntax wise is a forecast cluttered with generally chance pop
wording. /Pelatti
&&
.AVIATION...
00Z TAFS: An upper level low pressure area centered in the vicinity
of the aviation area allows for a cluttered forecast of primarily
showers at various times, either surface based or the elevated
forced type in the forecast for most of the time interval through
00Z Friday. These showers may produce MVFR ceilings at times.
Additionally some late night and early morning fog near rivers and
northern valleys could produce brief MVFR visibilities along with
some frost as temperatures drop below freezing for a brief spell
near KPUW, KDEW...and other more favorable aviation locations.
Additionally a very small potential for thunder exists near
Cascades and vicinity KLWS and portions of North Idaho Panhandle.
/Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 60 42 60 42 64 / 20 20 20 40 30 30
Coeur d`Alene 35 59 39 60 40 64 / 20 20 20 40 40 30
Pullman 32 59 39 57 40 64 / 20 20 20 40 20 30
Lewiston 38 66 45 64 45 71 / 20 20 10 40 20 30
Colville 35 63 39 68 41 69 / 70 30 30 50 40 40
Sandpoint 35 58 38 62 39 64 / 80 30 20 50 50 40
Kellogg 34 55 40 56 41 61 / 40 30 30 50 50 40
Moses Lake 39 66 43 69 45 72 / 20 20 20 30 20 10
Wenatchee 41 63 44 66 47 69 / 60 40 30 30 20 20
Omak 35 65 39 68 42 69 / 50 30 30 40 30 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning from 2 AM to 7 AM PDT Thursday for Idaho Palouse.
WA...Freeze Warning from 2 AM to 7 AM PDT Thursday for Washington
Palouse.
&&
$$
000
FXUS66 KSEW 222221
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
330 PM PDT WED MAY 22 2013
.SYNOPSIS...A COLD UPPER LEVEL LOW WILL GIVE SHOWERS WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS THROUGH THURSDAY. THE UPPER LOW
WILL WOBBLE AROUND THE PACIFIC NORTHWEST THROUGH THE MEMORIAL DAY
WEEKEND AS IT SLOWLY FILLS AND WEAKENS. COOL TEMPERATURES THROUGH
THURSDAY NIGHT WILL GRADUALLY MODERATE OVER THE WEEKEND AND SHOWERS
WILL GRADUALLY DIMINISH STARTING THURSDAY NIGHT.
&&
.SHORT TERM...PERSISTENT RAIN OVER THE SEATTLE AREA HAS ENDED BUT
THERE ARE STILL PLENTY OF SHOWERS OVER WESTERN SECTIONS. THE RAIN
AND CLOUDINESS ALONG WITH THE EVER PRESENT UPPER LEVEL LOW HAS LEFT
THE PUGET SOUND REGION ON THE COOL SIDE. KSEA HAS BEEN HOLDING
STEADY AT 50 DEGREES FOR A FEW HOURS AND MAY BREAK THE RECORD LOW
MAX OF 54 DEGREES FOR THIS DATE.
SHOWERS WILL TAPER TONIGHT BUT MAY GET ENERGIZED AGAIN THURSDAY
AFTERNOON AND EVENING. THERE IS SOME INSTABILITY IN THE MODELS SO
HAVE KEPT THE IDEA OF ISOLATED THUNDERSTORMS. THERE SHOULD AT LEAST
BE SOME SUN BREAKS SO TEMPERATURES WILL RISE...AT LEAST INTO THE LOW
60S OVER THE INTERIOR.
THE UPPER LEVEL LOW FINALLY STARTS TO FILL THURSDAY NIGHT AND
FRIDAY. THE GFS MOVES IT AWAY FROM THE AREA ON SATURDAY THOUGH THE
EURO DOES NOT. HAVE KEPT BASICALLY CHANCE POPS IN THE FORECAST WITH
A SLOW WARMING TREND. BURKE
.LONG TERM...SUNDAY COULD BE KIND OF A NICE DAY IF YOU BELIEVE THE
GFS. THE EURO STILL HAS THE UPPER LOW OVER THE AREA. PUT A MENTION
OF SUN IN THE SUNDAY FORECAST BUT KEPT THE CHANCE OF SHOWERS. THE
GFS BRINGS A WEAK SYSTEM INTO THE AREA MONDAY THROUGH TUESDAY WHILE
THE EURO STILL HAS THE SAME OR POSSIBLY A DIFFERENT UPPER LOW.
CONFIDENCE IS LOW IN ALL DETAILS BUT WENT WITH THE GFS SOLUTION AND
BOOSTED POPS INTO THE LIKELY CATEGORY TUESDAY AND TUESDAY NIGHT. BY
WEDNESDAY POPS DROP BACK TO CHANCE. BURKE
&&
.AVIATION...AN UPPER LOW WILL REMAIN OVER THE PACIFIC NORTHWEST...
CENTERED MAINLY OVER NORTH CENTRAL OREGON OR SOUTH CENTRAL
WASHINGTON TONIGHT AND SHIFTING INTO THE COASTAL WATERS THURSDAY.
THE AIR MASS OVER WESTERN WASHINGTON WILL BE MOIST AND WEAKLY
UNSTABLE. SHOWERY PRECIPITATION WILL CONTINUE...AND ISOLATED
THUNDERSTORMS ARE POSSIBLE MAINLY THURSDAY AFTERNOON AND EVENING.
THE CASCADES WILL REMAIN MOSTLY OBSCURED.
THERE IS A STILL A FAIRLY WIDE RANGE OF CONDITIONS ACROSS THE
FORECAST AREA THIS AFTERNOON. MVFR CEILINGS ARE COMMON OVER MUCH OF
THE PUGET SOUND REGION WHERE CONDITIONS HAVE BEEN SLOWLY
IMPROVING...WITH VFR CONDITIONS OVER MOST OF THE REST OF THE
FORECAST AREA. AT 2 PM SHOWERS WERE MAINLY TO THE SOUTH AND WEST OF
THE PUGET SOUND REGION...WITH LOCALLY MVFR VISIBILITIES AND
CEILINGS. GENERALLY SPEAKING THESE CONDITIONS SHOULD CONTINUE THIS
EVENING...WITH SOME DETERIORATION TONIGHT AND THEN IMPROVEMENT AGAIN
THURSDAY AFTERNOON.
KSEA...SOUTHWEST WIND 6-12 KT...BECOMING SOUTH TO SOUTHEAST 4-10 KT
TONIGHT AND SOUTHWEST AGAIN THURSDAY. THE THREAT OF THUNDERSTORMS AT
KSEA FOR THIS AFTERNOON AND EVENING LOOKS MINIMAL AT THIS TIME...BUT
THERE IS A 15 PERCENT CHANCE OF THUNDERSTORMS THURSDAY AFTERNOON AND
EVENING. MCDONNAL
&&
.MARINE...A 1010 MB LOW NEAR ALONG THE NORTHWEST SIDE OF VANCOUVER
ISLAND WILL WEAKEN AS IT MOVES SLOWLY SOUTH ACROSS THE WASHINGTON
OFFSHORE WATERS TONIGHT AND THURSDAY. IT WILL LIKELY BE OVER THE
NORTH OREGON OFFSHORE WATERS THURSDAY NIGHT.
THE MODELS HAVE BEEN SHOWING A WIDE RANGE OF SOLUTIONS WITH REGARD
TO THE MOVEMENT OF THE LOW AND ESPECIALLY THE WINDS IT WILL PRODUCE.
THAT IS STILL THE CASE. THE UW WRF-GFS STILL INDICATES SPOTTY
MARGINAL SMALL CRAFT ADVISORY SOUTHEAST WINDS THURSDAY OVER THE
COASTAL WATERS...AND IN THE STRAIT OF JUAN DE FUCA AND ADJACENT
INLAND WATERS. HOWEVER THE 12Z RUN HAS BACKED OFF SOMEWHAT FROM
PREVIOUS RUNS. OUR FORECAST WILL USE A MODEL BLEND...RESULTING IN
WINDS 20 KT OR LESS OVER THE COASTAL AND INLAND WATERS. THAT LOOKS
LIKE THE BEST FORECAST AT THIS TIME...BUT CERTAINLY SMALL CRAFT
ADVISORY WINDS SIMILAR TO THE UW WRF-GFS ARE POSSIBLE.
IN ADDITION WE HAVE MARGINAL SMALL CRAFT ADVISORY CONDITIONS OVER
THE COASTAL WATERS FOR HAZARDOUS SEAS THROUGH THIS EVENING...ALONG
WITH ROUGH BAR CONDITIONS AT GRAYS HARBOR THROUGH TONIGHT.
ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE SATURDAY AND SUNDAY.
SMALL CRAFT ADVISORY WINDS ARE POSSIBLE IN THE CENTRAL STRAIT OF
JUAN DE FUCA AND EAST ENTRANCE STRAIT FRIDAY THROUGH SUNDAY DURING
THE LATE AFTERNOON AND NIGHTTIME HOURS. A FRONT WILL APPROACH THE
FORECAST AREA FROM THE WEST MONDAY. MCDONNAL
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL WATERS THROUGH
THIS EVENING.
SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR
THROUGH TONIGHT.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KOTX 222153
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
253 PM PDT Wed May 22 2013
.SYNOPSIS...
a cool and wet period awaits the Inland Northwest care of a cold
upper level low. Occasional showers are expected each day through
the end of the week with cooler than normal temperatures. snow
will also be possible over the mountains. Conditions could
moderate a bit by the weekend as the low moves out of the area
but it will be replaced by another cool low sometime early next week.
&&
.DISCUSSION...
Tonight...Large closed low centered near Yakima this evening will
move northwest towards Seattle overnight. Models show the theta e
ridge axis which has brought heavy rain over the North Idaho
Panhandle and north Pend Oreille county shifting east into western
Montana this evening. A flood advisory remains in effect through
this evening for this area. The closed low position tonight will
result in south-southeast flow over Central and Eastern
Washington and North Idaho with showers rotating around the low.
LAPS data from this afternoon also has CAPE values of around 200
J/KG from Wenatchee through Hanford and the Blue Mountains which
could spark a stray thunderstorm. All models show a wedge of drier
air coming up from the south tonight which should dry most areas
out once evening showers die off with the loss of daytime heating.
However closer to the Cascades showers may persist overnight given
close proximity to low center.
With the drier air skies will have an opportunity to become mostly
clear or partly cloudy for Eastern Washington overnight. This
combined with a cool start with afternoon temperatures only in the
mid 40s over most areas will result in a cool night. Freezing
temperatures are expected for most locations on the Palouse and a
freeze warning has been issued. A tougher call for the northern
valleys where abundant boundary layer moisture may allow for more
fog or stratus to develop which would keep lows near or slightly
below freezing. With lower confidence opted to not include the
northern valleys, but colder spots like Republic and Deer Park
will have a good chance of reaching 30-32 degrees F. JW
.Thursday through Saturday...Cold upper level low will remain
the dominant feature through this period. Model solutions are
exhibiting very good agreement with the movement of the low and
the placement of the associated deformation band of precipitation.
The current deformation band which is responsible for the
widespread band of precipitation extending from NE Washington into
the central Panhandle...is expected to track E-NE overnight and
and move into NW Montana by late-morning or early afternoon. Drier
and more stable air is expected to move in its wake which will
likely bring a brief drying trend across much of the Inland NW at
least through the morning. The atmosphere is expected to
destabilize in the afternoon due to diurnal heating...and
scattered showers could develop over the eastern half of the
forecast area. Farther west...the presence of the low near the
mouth of the Columbia will result in weak upslope easterly flow
into the Cascades and keep more persistent shower activity fixed
over that region. Temperatures should moderate quite a bit
compared to today as a bit more sunshine is expected with the core
of the upper level low shifting the coldest air to our west.
By Thursday night into early Friday the low is expected to wobble
into central Oregon before heading north-northeast. This should
result in drying conditions for most locations. By Friday
afternoon...the models continue to exhibit great consistency by
showing the upper level low will wandering into NE Oregon with the
atmosphere over the Inland NW exhibiting a rapid destabilization.
Showers will likely become plentiful as model CAPE values climb
into the 250-500 j/kg range with no convective CAP. Given the
southerly mid-level flow...the most abundant activity will cluster
along the northern forecast zones adjacent to the Canadian border.
Thunderstorms look like a possibility given the stability
parameters...however the lack of strong ascent aloft the coverage
will be underwhelming.
For Saturday...the low will meander back west of the Cascades...
with the best chances of precipitation focusing over the northern
and western portions of the forecast area...near the Canadian
border and Cascades. Once again the instability parameters suggest
a small chance of thunderstorms...however most of the upper level
ascent will remain focused west of the Cascades. Temperatures will
continue to moderate through the period with highs climbing into
the mid 60s to lower 70s for most valley locations. fx
Saturday night through Wednesday...Long-wave trof continues to
influence the Western United States through this time
interval...therefore this interval remains marked with below
normal temperatures...lower than usual snow levels at times...and
moderate pops and amounts of precipitation at times. The flow
does become westerly enough and void of disturbances to allow for
some intervals of drying between shortwave passages but as far as
shortwave features traversing through there are just enough timing
differences in passing each one through (and there appears to be
about four or more) that there isn`t enough confidence to modify
any timing of each feature in the forecast...so the end result
syntax wise is a forecast cluttered with generally chance pop
wording. /Pelatti
&&
.AVIATION...
18Z TAFS: An upper low pivoting across the Columbia Basin and then
toward western Washington over the next 24 hours will bring bands
of rain to central/eastern WA and northern ID. Coverage is
expected to be highest through 20-22z over the eastern TAF sites,
before turning showery in the afternoon. The western TAF sites
will also see a modest chance of showers, with the easterly
upslope flow providing the most prolonged threat near KEAT.
A very moist boundary layer will lead to continued MVFR CIGS this
morning with gradual improvement through the day. Confidence is less
around the western TAF sites but the more persistent upslope flow
developing into KEAT may produce lower cigs for a longer period.
Isolated afternoon thunderstorm are possible near the Cascades and
central ID panhandle mtns, generally away from TAFs. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 60 42 60 42 64 / 20 20 20 40 30 30
Coeur d`Alene 35 59 39 60 40 64 / 20 20 20 40 40 30
Pullman 32 59 39 57 40 64 / 20 20 20 40 20 30
Lewiston 38 66 45 64 45 71 / 20 20 10 40 20 30
Colville 35 63 39 68 41 69 / 70 30 30 50 40 40
Sandpoint 35 58 38 62 39 64 / 80 30 20 50 50 40
Kellogg 34 55 40 56 41 61 / 40 30 30 50 50 40
Moses Lake 39 66 43 69 45 72 / 20 20 20 30 20 10
Wenatchee 41 63 44 66 47 69 / 60 40 30 30 20 20
Omak 35 65 39 68 42 69 / 50 30 30 40 30 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Freeze Warning from 2 AM to 7 AM PDT Thursday for Idaho Palouse.
WA...Freeze Warning from 2 AM to 7 AM PDT Thursday for Washington
Palouse.
&&
$$
000
FXUS66 KPQR 222050
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
150 PM PDT WED MAY 22 2013
.SYNOPSIS...A COLD UPPER LOW WILL REMAIN ANCHORED OVER THE
PACIFIC NW FOR THE REMAINDER OF THE WEEK...KEEPING A COOL SHOWERY
WEATHER PATTERN IN PLACE FOR THE NEXT FEW DAYS. THE LOW WILL WEAKEN
OVER THE WEEKEND...REDUCING THE CHANCES FOR SHOWERS...AND ALLOWING
TEMPERATURES TO WARM BACK CLOSER TO NORMAL.
&&
.SHORT TERM...UPPER LOW WAS SEEN IN SATELLITE PICTURES OVER
SOUTHCENTRAL WA THIS AFTERNOON...WITH WIDESPREAD RAIN AND IMBEDDED
SHOWERS OVER THE FORECAST AREA. A LAYER OF MOIST ISENTROPIC LIFT WAS
SEEN IN MODELS BETWEEN 285 AND 290K...COINCIDENT WITH THE MAIN AREA
OF RAIN. MODELS SUGGEST THE ISENTROPICS WEAKEN THIS AFTERNOON AND
EVENING...BUT WITH THE UPPER LOW REMAINING OVER WA OVERNIGHT...WILL
LEAVE POPS HIGH THROUGH MOST OF THE NIGHT. FOCUS FOR BEST
PRECIPITATION CHANCES SHIFTS TO THE NW PART OF THE AREA THU AS THE
MAIN LOBE ROTATING AROUND THE LOW MOVES S OVER THE WA COASTAL
WATERS...THEN INLAND OVER OREGON THU NIGHT. AFTER A DAY OF WHAT WILL
LIKELY BE RECORD COOL TODAY...TEMPERATURES SHOULD BE A BIT WARMER
THU DUE TO WARMING OF THE LOW AND A LACK OF PERSISTENT RAIN.
BY FRI MODELS AGREE THE CENTER OF THE LOW SHOULD BEGIN DRIFTING NE
OF THE REGION AS THE MAIN SHORTWAVE MOVES E AROUND THE BASE OF THE
LOW. WHILE MODELS SUGGEST SOME WEAKER SHORTWAVES DIGGING DOWN THE
BACK OF THE MAIN TROUGH...EXPECT TO SEE A DECREASE IN RAIN CHANCES
FRI INTO SAT. EXPECT TO SEE GRADUALLY WARMING TEMPS FRI AND SAT AS
THE UPPER FLOW BECOMES MORE WESTERLY.
.LONG TERM...SATURDAY EVENING THROUGH TUESDAY...SEVERAL SHORTWAVE
SYSTEMS ROTATE THROUGH A BROAD UPPER LEVEL LOW OVER THE NORTHEAST
PACIFIC AND WEST COAST. THE UPPER LOW LINGERS ACROSS THE REGION
THROUGH THE WEEKEND...KEEPING PERIODS OF SHOWERS AND BRIEF CLOUD
BREAKS IN THE FORECAST THROUGH THE WEEKEND. THE MODELS SHOW MORE
ORGANIZED SYSTEMS ARRIVING ALONG THE WEST COAST EARLY NEXT WEEK WITH
A CHANGE FROM INTERMITTENT SHOWERS TO STEADY RAIN LIKELY DURING THE
BEGINNING OF NEXT WEEK. SNOW LEVELS RISE SLIGHTLY EARLY NEXT WEEK
WITH TEMEPRATURES STILL REMAINING SLIGHTLY BELOW NORMAL. THERE IS
STILL NO TENDENCY IN THE LONG RANGE FORECAST FOR RIDGING TO RETURN
TO THE NORTHWEST. KWELSON
&&
.AVIATION...UPPER LOW OVER REGION WILL MOVE LITTLE TONIGHT. CURRENT
MIX OF MVFR AND VFR...WITH THE WORST OVER THE INTERIOR N OF KSLE.
LITTLE CHANGE THIS EVENING...WITH STEADY LIGHT RAIN AND MVFR
CONDITIONS. HIGHER CASCADES AND PASSES OBSCURED IN CLOUDS AND LIGHT
SNOW. PRECIP BECOMING MORE SHOWERY AFTER 05Z... WITH MOSTLY LOW VFR
AND HIGH END MVFR CIGS.
KPDX AND APPROACHES...MVFR CIGS AND STEADY RAIN THROUGH 06Z THEN
GRADUAL CHANGE OVER TO SHOWERS OCCASIONAL LIGHT RAIN. CIGS REMAIN
MVFR AT 1500 TO 2000 FT THRU 06Z...THEN SLIGHT IMPROVEMENT BUT
STILL HIGH MVFR. LOOKS LIKE LOW VFR CIGS AFTER 18Z THU. ROCKEY.
&&
.MARINE...LITTLE CHANGE. W TO NW WINDS CONTINUE...GENERALLY 10 TO
15 KT....BUT 15 TO 25 KT OVER THE FAR OUTER WATERS THIS EVENING.
WINDS EASE TONIGHT AS GRADIENTS RELAX. WINDS REMAIN 15 KT OR LESS
THROUGH SUN AS PRES GRADIENTS NOT ALL THAT STRONG. ANOTHER FRONT
WILL ARRIVE EARLY NEXT WEEK...WITH S TO SW WINDS UP TO 20 KT AGAIN.
SEAS GENERALLY 10 TO 13 FT TONIGHT...BUT WILL GRADUALLY SUBSIDE
LATER TONIGHT AND THU...DROPPING BELOW 10 FT LATE TONIGHT. SEAS
WILL CONTINUE TO GRADUALLY SUBSIDE THROUGH SUN. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 6 PM THIS EVENING FOR
THE OUTER WATERS...OR 10 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS THIS EVENING FOR
ALL COASTAL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR CONDITIONS TONIGHT.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 221801
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1101 AM PDT Wed May 22 2013
.SYNOPSIS...
The Inland Northwest will remain under a broad trough through at
least the middle of next week, with disturbances riding in from
the Pacific. This set up means several opportunities for
precipitation. Temperatures are expected to remain cooler than
normal through the end of this week, before some moderation.
&&
.DISCUSSION...
Rain wrapping around a large closed low centered near Hanford as
of 1030 am will continue to slowly migrate north today. A strong
wave rotating around this low will track from southeast Washington
and the Lewiston area late this morning into Northeast Washington
and the Idaho Panhandle early this afternoon...exiting the area
into southern British Columbia this evening. A band of steady rain
will move through these areas as this wave passes through. A theta
e ridge axis extending from near Lookout Pass to Bonners Ferry
will provide an axis of heavier rainfall with additional rainfall
totals of a half to three quarters of an inch expected. This is on
top of 1-1.5 inches of rain that has already fallen such that some
places may receive rainfall totals as high as 2-2.25 inches. With
this in mind and with a report of ponding of water on roads in
Boundary county opted to upgrade the flood watches to advisories.
Also, with persistent cloud cover today high temperatures were
lowered for most areas. JW
&&
.AVIATION...
18Z TAFS: An upper low pivoting across the Columbia Basin and then
toward western Washington over the next 24 hours will bring bands
of rain to central/eastern WA and northern ID. Coverage is
expected to be highest through 20-22z over the eastern TAF sites,
before turning showery in the afternoon. The western TAF sites
will also see a modest chance of showers, with the easterly
upslope flow providing the most prolonged threat near KEAT.
A very moist boundary layer will lead to continued MVFR CIGS this
morning with gradual improvement through the day. Confidence is less
around the western TAF sites but the more persistent upslope flow
developing into KEAT may produce lower cigs for a longer period.
Isolated afternoon thunderstorm are possible near the Cascades and
central ID panhandle mtns, generally away from TAFs. JW
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 48 36 61 44 62 41 / 90 20 20 10 50 40
Coeur d`Alene 45 35 61 41 61 40 / 80 20 20 20 50 60
Pullman 48 34 61 40 58 40 / 90 20 20 20 60 50
Lewiston 56 39 67 46 65 46 / 90 20 20 20 60 50
Colville 48 36 66 41 69 40 / 90 60 30 20 40 50
Sandpoint 43 35 60 40 62 39 / 90 70 30 20 50 60
Kellogg 43 34 56 42 58 41 / 80 40 30 40 60 60
Moses Lake 55 40 67 45 70 44 / 50 20 30 20 30 20
Wenatchee 52 40 65 45 66 46 / 70 60 40 20 30 20
Omak 50 36 66 41 69 42 / 80 50 40 20 30 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
000
FXUS66 KSEW 221647 CCA
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 AM PDT WED MAY 22 2013
CORRECTED TO ADD WINTER WEATHER ADVISORY.
.SYNOPSIS...A COLD UPPER LEVEL LOW WILL GIVE SHOWERS WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS THROUGH THURSDAY. THE UPPER LOW
WILL WOBBLE AROUND THE PACIFIC NORTHWEST THROUGH THE MEMORIAL DAY
WEEKEND AS IT SLOWLY FILLS AND WEAKENS. COOL TEMPERATURES THROUGH
THURSDAY NIGHT WILL GRADUALLY MODERATE OVER THE WEEKEND AND SHOWERS
WILL GRADUALLY DIMINISH STARTING THURSDAY NIGHT.
&&
.SHORT TERM...UPPER LEVEL LOW APPEARS TO BE CENTERED SOMEWHERE OVER
SOUTHEAST WASHINGTON THIS MORNING. SHOWERS ARE ROTATING AROUND THE
LOW SO ONE BATCH IS MOVING EAST TO WEST OVER PUGET SOUND WHILE
ANOTHER MOVES INTO THE SOUTH COAST WEST TO EAST. KSEA HAS HAD A
PERSISTENT SHOWER THIS MORNING WITH OVER FOUR TENTHS OF AN INCH SO
FAR. TODAY WILL DEFINITELY BE SHOWERY...WITH SOMEWHAT FEWER SHOWERS
OVER THE NORTH PART. AS THE LOW MOVES NORTH A BIT THIS AFTERNOON THE
SHOWER THREAT WILL ALSO SHIFT NORTH. THERE COULD BE ISOLATED
THUNDERSTORMS THIS AFTERNOON AND EVENING...SOME WITH SMALL HAIL.
WITH SUBSTANTIAL PERSISTENT CLOUD COVER...TEMPERATURES ARE UNLIKELY
TO GET OUT OF THE 50S TODAY...EXCEPT POSSIBLY IN THE FAR NORTH.
PARADISE ON MOUNT RAINIER HAS RECEIVED NEARLY A FOOT OF NEW SNOW
SINCE LAST NIGHT. THE SNOW LEVEL HAS FALLEN TO NEAR 2000 FEET AROUND
THE MOUNTAIN...WITH ACCUMULATION OCCURRING AT LONGMIRE. WILL SEE HOW
THINGS ARE GOING THIS AFTERNOON AND MAY KEEP THE WINTER WEATHER
ADVISORY FOR THE CENTRAL CASCADES GOING.
THE UPPER LEVEL LOW WILL MOVE RIGHT OVER WESTERN WASHINGTON
THURSDAY. THIS WILL KEEP THE SHOWER THREAT GOING AND AGAIN MAKE
ISOLATED THUNDERSTORMS A POSSIBILITY. HIGH TEMPERATURES SHOULD TICK
UP A BIT AS HEIGHTS RISE.
THOUGH THE UPPER LOW WILL STILL BE HANGING AROUND...MODELS SHOW
CONSIDERABLY LESS SHOWER ACTIVITY THURSDAY NIGHT AND FRIDAY. THERE
WILL PROBABLY BE SOME DIURNAL ENHANCEMENT FRIDAY AFTERNOON AND
EVENING...ESPECIALLY IN THE MOUNTAINS. THERE WILL BE MORE SUN AND
HIGHER TEMPERATURES ON FRIDAY. BURKE
.LONG TERM...PREVIOUS DISCUSSION...THE UPPER LOW WILL TEND TO
RETROGRADE TO JUST OFFSHORE SATURDAY THEN SHIFT BACK INLAND SUNDAY.
THIS WILL GENERALLY RESULT IN DIURNAL MAINLY MOUNTAIN SHOWERS WITH
TEMPERATURES A FEW DEGREES BELOW NORMAL THROUGH MUCH OF THE MEMORIAL
DAY WEEKEND. MEMORIAL DAY WEATHER IS UP IN THE AIR AS ALL MODELS
BRING A BRIEF WEAK SHORTWAVE RIDGE THROUGH THE AREA SOMETIME LATE
SUNDAY NIGHT OR MEMORIAL DAY FOLLOWED BY A STRONGER FRONTAL SYSTEM
ASSOCIATED WITH A DEEPER UPPER LOW OFFSHORE BY TUESDAY. THERE IS
LITTLE SKILL IN FORECASTING THESE FEATURES SEVERAL DAYS OUT.
FORECASTS SATURDAY ONWARD WERE NOT ALTERED EARLY THIS MORNING.
ALBRECHT
&&
.AVIATION...AN UPPER LOW WILL REMAIN OVER THE PACIFIC NORTHWEST
THROUGH TONIGHT...CENTERED MAINLY OVER NORTH CENTRAL OREGON OR SOUTH
CENTRAL WASHINGTON. THE AIR MASS OVER WESTERN WASHINGTON WILL BE
MOIST AND WEAKLY UNSTABLE. SHOWERY PRECIPITATION WILL CONTINUE TODAY
AND TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING MAINLY OVER THE PUGET SOUND REGION...SOUTHWEST INTERIOR...
AND THE CASCADES. THE CASCADES WILL REMAIN MOSTLY OBSCURED.
THERE IS A WIDE RANGE OF CONDITIONS ACROSS THE FORECAST AREA THIS
MORNING. IFR VISIBILITY AND CEILINGS ARE COMMON OVER MUCH OF THE
PUGET SOUND REGION...WITH VFR CONDITIONS OVER MUCH OF THE NORTH
INTERIOR AND ALONG THE COAST. THESE CONDITIONS ARE HIGHLY SUBJECT TO
CHANGE ACCORDING TO THE DEVELOPMENT AND MOVEMENT OF SHOWERS...
HOWEVER THERE SHOULD BE GENERALLY AN IMPROVING TREND WITH LOW-END
VFR CONDITIONS COMMON ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. SOME DETERIORATION IS LIKELY AGAIN TONIGHT.
KSEA...SOUTH WIND 6-12 KT...BECOMING SOUTHWEST THIS AFTERNOON AND
EVENING...THEN BACKING TO SOUTH AGAIN TONIGHT. THERE IS A 15 PERCENT
CHANCE OF THUNDERSTORMS AT KSEA THIS AFTERNOON AND EVENING. MCDONNAL
&&
.MARINE...A 1008 MB LOW NEAR THE NORTHWEST TIP OF VANCOUVER ISLAND
WILL WEAKEN AS IT MOVES SLOWLY SOUTH ACROSS THE WASHINGTON OFFSHORE
WATERS TODAY THROUGH THURSDAY. IT WILL LIKELY BE OVER THE NORTH
OREGON OFFSHORE WATERS THURSDAY NIGHT. THERE IS A GOOD CHANCE THAT
THE LOW WILL PRODUCE SMALL CRAFT ADVISORY SOUTH OR SOUTHEAST WINDS
OVER THE COASTAL WATERS THURSDAY...AND MARGINAL SMALL CRAFT ADVISORY
SOUTHEAST WINDS ARE POSSIBLE IN THE INLAND WATERS ZONES AS WELL.
MODELS CONTINUE TO DIFFER CONSIDERABLY IN THIS REGARD.
IN ADDITION WE HAVE MARGINAL SMALL CRAFT ADVISORY CONDITIONS OVER
THE COASTAL WATERS FOR HAZARDOUS SEAS THROUGH THIS EVENING...ALONG
WITH ROUGH BAR CONDITIONS AT GRAYS HARBOR.
ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE SATURDAY AND SUNDAY.
SMALL CRAFT ADVISORY WINDS ARE POSSIBLE IN THE CENTRAL STRAIT OF
JUAN DE FUCA AND EAST ENTRANCE STRAIT FRIDAY THROUGH SUNDAY DURING
THE LATE AFTERNOON AND NIGHTTIME HOURS. MCDONNAL
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...WINTER WEATHER ADVISORY CENTRAL CASCADES.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL WATERS THROUGH
THIS EVENING.
SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR
THROUGH TONIGHT.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KSEW 221609
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
910 AM PDT WED MAY 22 2013
.SYNOPSIS...A COLD UPPER LEVEL LOW WILL GIVE SHOWERS WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS THROUGH THURSDAY. THE UPPER LOW
WILL WOBBLE AROUND THE PACIFIC NORTHWEST THROUGH THE MEMORIAL DAY
WEEKEND AS IT SLOWLY FILLS AND WEAKENS. COOL TEMPERATURES THROUGH
THURSDAY NIGHT WILL GRADUALLY MODERATE OVER THE WEEKEND AND SHOWERS
WILL GRADUALLY DIMINISH STARTING THURSDAY NIGHT.
&&
.SHORT TERM...UPPER LEVEL LOW APPEARS TO BE CENTERED SOMEWHERE OVER
SOUTHEAST WASHINGTON THIS MORNING. SHOWERS ARE ROTATING AROUND THE
LOW SO ONE BATCH IS MOVING EAST TO WEST OVER PUGET SOUND WHILE
ANOTHER MOVES INTO THE SOUTH COAST WEST TO EAST. KSEA HAS HAD A
PERSISTENT SHOWER THIS MORNING WITH OVER FOUR TENTHS OF AN INCH SO
FAR. TODAY WILL DEFINITELY BE SHOWERY...WITH SOMEWHAT FEWER SHOWERS
OVER THE NORTH PART. AS THE LOW MOVES NORTH A BIT THIS AFTERNOON THE
SHOWER THREAT WILL ALSO SHIFT NORTH. THERE COULD BE ISOLATED
THUNDERSTORMS THIS AFTERNOON AND EVENING...SOME WITH SMALL HAIL.
WITH SUBSTANTIAL PERSISTENT CLOUD COVER...TEMPERATURES ARE UNLIKELY
TO GET OUT OF THE 50S TODAY...EXCEPT POSSIBLY IN THE FAR NORTH.
PARADISE ON MOUNT RAINIER HAS RECEIVED NEARLY A FOOT OF NEW SNOW
SINCE LAST NIGHT. THE SNOW LEVEL HAS FALLEN TO NEAR 2000 FEET AROUND
THE MOUNTAIN...WITH ACCUMULATION OCCURRING AT LONGMIRE. WILL SEE HOW
THINGS ARE GOING THIS AFTERNOON AND MAY KEEP THE WINTER WEATHER
ADVISORY FOR THE CENTRAL CASCADES GOING.
THE UPPER LEVEL LOW WILL MOVE RIGHT OVER WESTERN WASHINGTON
THURSDAY. THIS WILL KEEP THE SHOWER THREAT GOING AND AGAIN MAKE
ISOLATED THUNDERSTORMS A POSSIBILITY. HIGH TEMPERATURES SHOULD TICK
UP A BIT AS HEIGHTS RISE.
THOUGH THE UPPER LOW WILL STILL BE HANGING AROUND...MODELS SHOW
CONSIDERABLY LESS SHOWER ACTIVITY THURSDAY NIGHT AND FRIDAY. THERE
WILL PROBABLY BE SOME DIURNAL ENHANCEMENT FRIDAY AFTERNOON AND
EVENING...ESPECIALLY IN THE MOUNTAINS. THERE WILL BE MORE SUN AND
HIGHER TEMPERATURES ON FRIDAY. BURKE
.LONG TERM...PREVIOUS DISCUSSION...THE UPPER LOW WILL TEND TO
RETROGRADE TO JUST OFFSHORE SATURDAY THEN SHIFT BACK INLAND SUNDAY.
THIS WILL GENERALLY RESULT IN DIURNAL MAINLY MOUNTAIN SHOWERS WITH
TEMPERATURES A FEW DEGREES BELOW NORMAL THROUGH MUCH OF THE MEMORIAL
DAY WEEKEND. MEMORIAL DAY WEATHER IS UP IN THE AIR AS ALL MODELS
BRING A BRIEF WEAK SHORTWAVE RIDGE THROUGH THE AREA SOMETIME LATE
SUNDAY NIGHT OR MEMORIAL DAY FOLLOWED BY A STRONGER FRONTAL SYSTEM
ASSOCIATED WITH A DEEPER UPPER LOW OFFSHORE BY TUESDAY. THERE IS
LITTLE SKILL IN FORECASTING THESE FEATURES SEVERAL DAYS OUT.
FORECASTS SATURDAY ONWARD WERE NOT ALTERED EARLY THIS MORNING.
ALBRECHT
&&
.AVIATION...AN UPPER LOW WILL REMAIN OVER THE PACIFIC NORTHWEST
THROUGH TONIGHT...CENTERED MAINLY OVER NORTH CENTRAL OREGON OR SOUTH
CENTRAL WASHINGTON. THE AIR MASS OVER WESTERN WASHINGTON WILL BE
MOIST AND WEAKLY UNSTABLE. SHOWERY PRECIPITATION WILL CONTINUE TODAY
AND TONIGHT. ISOLATED THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON AND
EVENING MAINLY OVER THE PUGET SOUND REGION...SOUTHWEST INTERIOR...
AND THE CASCADES. THE CASCADES WILL REMAIN MOSTLY OBSCURED.
THERE IS A WIDE RANGE OF CONDITIONS ACROSS THE FORECAST AREA THIS
MORNING. IFR VISIBILITY AND CEILINGS ARE COMMON OVER MUCH OF THE
PUGET SOUND REGION...WITH VFR CONDITIONS OVER MUCH OF THE NORTH
INTERIOR AND ALONG THE COAST. THESE CONDITIONS ARE HIGHLY SUBJECT TO
CHANGE ACCORDING TO THE DEVELOPMENT AND MOVEMENT OF SHOWERS...
HOWEVER THERE SHOULD BE GENERALLY AN IMPROVING TREND WITH LOW-END
VFR CONDITIONS COMMON ACROSS THE AREA LATE THIS AFTERNOON AND
EVENING. SOME DETERIORATION IS LIKELY AGAIN TONIGHT.
KSEA...SOUTH WIND 6-12 KT...BECOMING SOUTHWEST THIS AFTERNOON AND
EVENING...THEN BACKING TO SOUTH AGAIN TONIGHT. THERE IS A 15 PERCENT
CHANCE OF THUNDERSTORMS AT KSEA THIS AFTERNOON AND EVENING. MCDONNAL
&&
.MARINE...A 1008 MB LOW NEAR THE NORTHWEST TIP OF VANCOUVER ISLAND
WILL WEAKEN AS IT MOVES SLOWLY SOUTH ACROSS THE WASHINGTON OFFSHORE
WATERS TODAY THROUGH THURSDAY. IT WILL LIKELY BE OVER THE NORTH
OREGON OFFSHORE WATERS THURSDAY NIGHT. THERE IS A GOOD CHANCE THAT
THE LOW WILL PRODUCE SMALL CRAFT ADVISORY SOUTH OR SOUTHEAST WINDS
OVER THE COASTAL WATERS THURSDAY...AND MARGINAL SMALL CRAFT ADVISORY
SOUTHEAST WINDS ARE POSSIBLE IN THE INLAND WATERS ZONES AS WELL.
MODELS CONTINUE TO DIFFER CONSIDERABLY IN THIS REGARD.
IN ADDITION WE HAVE MARGINAL SMALL CRAFT ADVISORY CONDITIONS OVER
THE COASTAL WATERS FOR HAZARDOUS SEAS THROUGH THIS EVENING...ALONG
WITH ROUGH BAR CONDITIONS AT GRAYS HARBOR.
ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE SATURDAY AND SUNDAY.
SMALL CRAFT ADVISORY WINDS ARE POSSIBLE IN THE CENTRAL STRAIT OF
JUAN DE FUCA AND EAST ENTRANCE STRAIT FRIDAY THROUGH SUNDAY DURING
THE LATE AFTERNOON AND NIGHTTIME HOURS. MCDONNAL
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS COASTAL WATERS THROUGH
THIS EVENING.
SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR
THROUGH TONIGHT.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KOTX 221558
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
858 AM PDT Wed May 22 2013
.SYNOPSIS...
The Inland Northwest will remain under a broad trough through at
least the middle of next week, with disturbances riding in from
the Pacific. This set up means several opportunities for
precipitation. Temperatures are expected to remain cooler than
normal through the end of this week, before some moderation.
&&
.DISCUSSION...
A large closed low near the Tri Cities will continue to produce
wrap around precipitation in the form of rain and mountain snow
today. This morning the heaviest rain will be focused along a
theta e ridge axis over far North Idaho...and in the Wenatchee
area given closest proximity to closed low with low level upslope
flow enhancing precip. Web cameras at Blewett and Stevens Pass
show this precipitation falling as snow this morning but with
roadways wet. This low is expected to migrate north slowly today
with the axis of more persistent rainfall moving north of the
Columbia Basin in the afternoon. However under the cold pool of
-30C at 500mb showers and isolated thunderstorms will develop
behind the main band of stratiform rain around Wenatchee and Moses
Lake. The forecast has been updated to increase precipitation
chances and rainfall amounts for today especially the Okanogan
Valley. Will likely need to evaluate high temperatures today as
forecast values may be slightly too high due to persistent cloud
cover especially near the Cascades, Spokane/Coeur D`Alene area,
and northern valleys. JW
&&
.AVIATION...
12Z TAFS: An upper low pivoting across the Columbia Basin and then
toward western Washington over the next 24 hours will bring bands
of rain to central/eastern WA and northern ID. Coverage is
expected to be best this morning and early afternoon over the
eastern TAF sites, before turning showery in the afternoon. Some
light snow may be mixed in during the morning. The western TAF
sites will also see a modest chance of showers, with the easterly
upslope flow providing the most prolonged threat near KEAT.
Confidence is low with regard to the precise ceilings, but look
for IFR/MVFR cigs over the eastern TAFs much of the morning with
improvement by the afternoon/evening. Confidence is less around
the western TAF sites but the more persistent upslope flow
developing into KEAT may produce lower cigs for a longer period.
Isolated afternoon thunderstorm are possible near the Cascades and
central ID panhandle mtns, generally away from TAFs. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 36 61 44 62 41 / 90 20 20 10 50 40
Coeur d`Alene 48 35 61 41 61 40 / 90 20 20 20 50 60
Pullman 50 34 61 40 58 40 / 90 20 20 20 60 50
Lewiston 58 39 67 46 65 46 / 90 20 20 20 60 50
Colville 54 36 66 41 69 40 / 100 60 30 20 40 50
Sandpoint 49 35 60 40 62 39 / 100 70 30 20 50 60
Kellogg 46 34 56 42 58 41 / 90 40 30 40 60 60
Moses Lake 59 40 67 45 70 44 / 50 20 30 20 30 20
Wenatchee 55 40 65 45 66 46 / 100 60 40 20 30 20
Omak 56 36 66 41 69 42 / 100 50 40 20 30 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Flood Watch through this evening for Northern Panhandle.
WA...Flood Watch through this evening for Northeast Mountains.
&&
$$
000
FXUS66 KPQR 221527
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
826 AM PDT WED MAY 22 2013
.SYNOPSIS...A COLD UPPER LOW WILL REMAIN ANCHORED OVER THE
PACIFIC NW FOR THE REMAINDER OF THE WEEK...KEEPING A COOL SHOWERY
WEATHER PATTERN IN PLACE FOR THE NEXT FEW DAYS. THE LOW WILL WEAKEN
OVER THE WEEKEND...REDUCING THE CHANCES FOR SHOWERS...AND ALLOWING
TEMPERATURES TO WARM BACK CLOSER TO NORMAL.
&&
.SHORT TERM...WATER VAPOR PICTURES SHOWED THE UPPER LOW OVER
SOUTHCENTRAL WA THIS MORNING...WITH RADAR INDICATING WIDESPREAD
SHOWERS. WITH ONSHORE LOW LEVEL FLOW TODAY AND THE UPPER LOW
REMAINING OVER THE REGION...NO REASON TO EXPECT SHOWERS TO ABATE.
WITH LOW FREEZING LEVELS...WILL KEEP A MENTION OF SMALL HAIL IN WITH
THE SHOWERS TODAY.
THE UPPER LEVEL LOW WITH A COUPLE OF SHORTWAVES PIN-WHEELING AROUND
IT WILL CONTINUE TO DRIVE THE WEATHER THROUGH FRIDAY. THE WEATHER
PATTERN WILL BE FAIRLY PERSISTENT WITH SHOWERS AND UNSEASONAL COOL
TEMPERATURES BEING THE DOMINANT FEATURES. MODELS HINT OF WEAK
INSTABILITY ACROSS THE REGION EACH DAY BUT THINK THE BEST CHANCE FOR
THUNDERSTORMS REMAINS OUTSIDE OF THE PORTLAND FORECAST AREA.
SNOW LEVELS WILL REMAIN AROUND 3 KFT TODAY..THEN GRADUALLY RISE
THURSDAY AND FRIDAY. SNOW LEVELS SHOULD RISE ABOVE PASS LEVEL ON
FRIDAY. EXPECT AN ADDITIONAL 1 TO 3 INCHES OF SNOW ABOVE 3000 FEET
TODAY.
.LONG TERM...THE LOW WILL WEAKEN ON FRIDAY BUT LINGER AROUND OVER THE
AREA THROUGH THE WEEKEND. MODELS ARE TRYING TO BRING A SHORTWAVE
RIDGE OVER THE AREA BRIEFLY ON MONDAY...BUT MOIST ONSHORE FLOW WILL
PREVENT TOTAL DRYING. ANOTHER STORM IS EXPECTED EARLY NEXT WEEK...MON
NIGHT OR TUE.
&&
.AVIATION...NOT A GOOD DAY FOR FLYING. CURRENTLY HAVE A MIX OF MVFR
AND VFR...WITH THE WORST OVER THE INTERIOR. CONDITIONS WILL
GRADUALLY DETERIORATE LATER THIS AM AS A MORE STEADY RAIN AND MVFR
CONDITIONS ARRIVES. LITTLE CHANGE THROUGH EARLY EVENING...WITH
HIGHER CASCADES AND PASSES OBSCURED IN CLOUDS AND SNOW. PRECIP
BECOMING MORE SHOWERY AFTER 03Z... WITH MOSTLY LOW VFR AND HIGH END
MVFR CIGS.
KPDX AND APPROACHES...MVFR CIGS AND RAIN ON TAP THROUGH 03Z. WILL
SEE BRIEF BREAKS BETWEEN THE MVFR...BUT OVERALL CIGS 1500 TO 2000
THROUGH 03Z. TURNING MORE SHOWERY TONIGHT. BUT CIGS LOW VFR WITH
OCCASIONAL MVFR CIGS DUE TO COOL MOIST AIR MASS REMAINING. ROCKEY.
&&
.MARINE...LITTLE CHANGE. W TO NW WINDS CONTINUE...GENERALLY IN 10
TO 15 KT. GUSTS UP TO 25 KT ON THE OUTER WATERS CONTINUE TODAY.
WINDS WILL EASE BACK SIGNIFICANTLY TONIGHT AS GRADIENTS RELAX.
NOT MUCH WINDS THROUGH SUN AS LOWER PRES REMAINS OVER THE REGION.
SEAS GENERALLY 10 TO 12 FT TODAY AND TONIGHT. SEAS GRADUALLY
SUBSIDE THU...DROPPING BELOW 10 FT BY MIDDAY THU. SEAS WILL
CONTINUE TO GRADUALLY SUBSIDE THROUGH SUN. ROCKEY.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM THIS AFTERNOON FOR
THE OUTER COASTAL WATERS...FROM 10 TO 60 NM OFFSHORE.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL MIDNIGHT TONIGHT
FOR ALL COASTAL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA BAR CONDITIONS THROUGH
THIS EVENING.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 221155
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
455 AM PDT Wed May 22 2013
.SYNOPSIS...
The Inland Northwest will remain under a broad trough through at
least the middle of next week, with disturbances riding in from
the Pacific. This set up means several opportunities for
precipitation. Temperatures are expected to remain cooler than
normal through the end of this week, before some moderation.
&&
.DISCUSSION...
Today and tonight: An upper low will continue take hold of the
West with cooler than normal and occasionally wet conditions.
Early this morning the center of low was situated near Redmond,
Oregon. All guidance tracks it into the Columbia Basin by midday,
before its tracks northwest toward the Puget Sound tonight.
Meanwhile at the surface a deformation axis/trough stretched from
the ID/MT border to northeast WA is projected to edge north and
east. For today these two features will provide a high threat of
showers across the central Cascades, portions of the Wenatchee
through Moses Lake zones, and the central and northern Idaho
Panhandle and northeast Washington mountain.
A flood watch continues for parts of northeast Washington and the
northern Panhandle through this evening (06Z Thursday). The region
received some moderate rainfall amounts Tuesday. With
precipitation continuing to train across this region this morning
and more expected through the day, this will make the region
susceptible to flooding. This is especially in the hillier/steep
terrain, low spots and near smaller streams/creeks.
Elsewhere models suggest a migratory precipitation threat. As the
upper low pivots north showers are expected to expand, first over
the east third and north-central WA this morning and second toward
midday/early afternoon into the Okanogan Valley, Waterville Plateau
and northern Cascades. By tonight the low migrates into the
Cascades and eventually western Washington and the deformation
axis near the Panhandle edges northeast, while drier air comes in
from the southeast. The easterly flow will continue to provide
high precipitation chances into the Cascades and across the
northern mountains, but the threat will begin to wane as the night
progresses. The shower threat elsewhere will be dwindling as drier
air comes in.
Some instability around the center of the low, indicated by High
Level Total Totals around 30-38C and low-grade CAPE around 100-150
J/kg, will provide at least an isolated thunderstorm threat near
the Cascades through the Upper Columbia Basin, as well as in the
vicinity of the Blue Mountains.
Snow levels around the upper low are expected to be near the
3000-4000 foot mark much of the period. Snow levels elsewhere
around 5000-7000 feet (highest toward the northern Panhandle) are
expected to lower to between 4000-5000 feet through the day. Thus
some snow or at least a rain/snow mix is likely to be seen around
the Blues, the Camas Prairie and mountain passes. There is the
potential for some snow even around the higher Palouse, including
the Pullman area, this morning.
Temperatures are expected to be held much below normal under the
cool core of the upper low. This means many areas struggling to
get into the 50s today. As for overnight lows tonight into
Thursday morning, we will have to monitor reading for potential
freezing warnings. Possible locations include the Okanogan
Highlands through the northern Panhandle, as well as the Palouse.
/J. Cote`
Thursday through Tuesday...Model agreement is quite good through
Friday...with some deterioration in detail commonality after
Friday but still display reasonable agreement regarding the over
all flow regime over and near the forecast area.
Thursday through Friday the upper level closed low is firmly
planted over the forecast area. The deformation band of persistent
and frequent showers currently entering the region will be off to
the north over southern BC and Alberta by Thursday morning...but
the forecast area will be under the direct influence of the low
center cold pool aloft with minor vorticity spokes available to
gin up showers in this weakly unstable and moist air mass. This
argues for a cool and showery regime with plenty of clouds and the
possibility of some fairly weak and isolated thunderstorms.
Impossible to nail down these sub-synoptic inter-trough
disturbances at this time...but suffice it to say just about
anywhere in the forecast area will be at risk for a shower or two
each day with the best chance over the mountains ringing the basin.
The holiday weekend harbors no better news for outdoor
enthusiasts. The good news is that the stubborn upper low will
weaken and become less coherent...but the bad news is a general
troffy pattern will remain over the region through the weekend.
Both the latest GFS and ECMWF place the axis of this opening
system/trough off the coast...which implies warmer temperatures in
a pre-trough southwest flow regime. However the area will remain
under cyclonic difluent flow aloft with likely a few sub-synoptic
disturbances rounding this flow Saturday through Monday. This
overall pattern does not suggest a particularly wet period...but
the risk of showers...particularly over the northern and eastern
mountains will present itself each day. Both models hint that the
highest risk of showers associated with a stronger disturbance
will be on Sunday and focused over the southeast and Idaho
Panhandle.
Tuesday the flow becomes a bit more progressive...but also brings
the threat of a stronger wave and surface occlusion to enhance
chances of rain once again.
Overall...there is high confidence of a distinctly unsettled and
occasionally showery regime right through the next week with low
confidence in timing any periods of heightened shower activity.
Temperatures will start out below normal Thursday and gradually
achieve seasonably normal values this weekend. /Fugazzi
&&
.AVIATION...
12Z TAFS: An upper low pivoting across the Columbia Basin and then
toward western Washington over the next 24 hours will bring bands
of rain to central/eastern WA and northern ID. Coverage is
expected to be best this morning and early afternoon over the
eastern TAF sites, before turning showery in the afternoon. Some
light snow may be mixed in during the morning. The western TAF
sites will also see a modest chance of showers, with the easterly
upslope flow providing the most prolonged threat near KEAT.
Confidence is low with regard to the precise ceilings, but look
for IFR/MVFR cigs over the eastern TAFs much of the morning with
improvement by the afternoon/evening. Confidence is less around
the western TAF sites but the more persistent upslope flow
developing into KEAT may produce lower cigs for a longer period.
Isolated afternoon thunderstorm are possible near the Cascades and
central ID panhandle mtns, generally away from TAFs. /J. Cote`
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 36 61 44 62 41 / 80 20 20 10 50 40
Coeur d`Alene 48 35 61 41 61 40 / 90 20 20 20 50 60
Pullman 50 34 61 40 58 40 / 70 20 20 20 60 50
Lewiston 58 39 67 46 65 46 / 50 20 20 20 60 50
Colville 54 36 66 41 69 40 / 90 60 30 20 40 50
Sandpoint 49 35 60 40 62 39 / 100 70 30 20 50 60
Kellogg 46 34 56 42 58 41 / 90 40 30 40 60 60
Moses Lake 59 40 67 45 70 44 / 50 20 30 20 30 20
Wenatchee 55 40 65 45 66 46 / 60 40 40 20 30 20
Omak 56 36 66 41 69 42 / 70 50 40 20 30 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Flood Watch through this evening for Northern Panhandle.
WA...Flood Watch through this evening for Northeast Mountains.
&&
$$
000
FXUS66 KPQR 221020
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
320 AM PDT WED MAY 22 2013
.SYNOPSIS...A COLD UPPER LOW WILL REMAIN ANCHORED OVER THE
PACIFIC NW FOR THE REMAINDER OF THE WEEK...KEEPING A COOL SHOWERY
WEATHER PATTERN IN PLACE FOR THE NEXT FEW DAYS. THE LOW WILL WEAKEN
OVER THE WEEKEND...REDUCING THE CHANCES FOR SHOWERS...AND ALLOWING
TEMPERATURES TO WARM BACK CLOSER TO NORMAL.
&&
.SHORT TERM...AN UPPER LEVEL LOW WITH A COUPLE OF SHORTWAVES
PIN-WHEELING AROUND IT WILL DRIVE THE WEATHER THROUGH FRIDAY. THE
WEATHER PATTERN WILL BE FAIRLY PERSISTENT WITH SHOWERS AND UNSEASONAL
COOL TEMPERATURES BEING THE DOMINANT FEATURES. THE SHOWERS WILL
BECOME ENHANCED THIS AFTERNOON...ESPECIALLY OVER THE MOUNTAINS AND
MAY HAVE PERIODIC SHORT BURSTS OF LOCALLY HEAVY RAIN. MODELS HINT OF
WEAK INSTABILITY ACROSS THE REGION EACH DAY BUT THINK THE BEST CHANCE
FOR THUNDERSTORMS REMAINS OUTSIDE OF THE PORTLAND FORECAST AREA.
SNOW LEVELS WILL REMAIN AROUND 3 KFT TODAY..THEN GRADUALLY RISE
THURSDAY AND FRIDAY. SNOW LEVELS SHOULD RISE ABOVE PASS LEVEL ON
FRIDAY. EXPECT AN ADDITIONAL 1 TO 3 INCHES OF SNOW ABOVE 3000 FEET
TODAY.
.LONG TERM...THE LOW WILL WEAKEN ON FRIDAY BUT LINGER AROUND OVER THE
AREA THROUGH THE WEEKEND. MODELS ARE TRYING TO BRING A SHORTWAVE
RIDGE OVER THE AREA BRIEFLY ON MONDAY...BUT MOIST ONSHORE FLOW WILL
PREVENT TOTAL DRYING. ANOTHER STORM IS EXPECTED EARLY NEXT WEEK...MON
NIGHT OR TUE.
&&
.AVIATION...MOSTLY VFR CONDITIONS CURRENTLY WITH SCATTERED SHOWER
ACTIVITY ACROSS THE REGION THIS MORNING. EXPECT SHOWER ACTIVITY TO
INCREASE AFTER 12Z...WITH PERIODS OF MVFR CIGS AT TIMES DURING
HEAVIER SHOWERS. A DISTURBANCE EMBEDDED IN THE LARGE SCALE UPPER
LEVEL LOW WILL BRING STEADIER RAIN DURING THE LATE MORNING AND
AFTERNOON HOURS. EXPECT MORE WIDESPREAD MVFR CONDITIONS FROM
ROUGHLY 18Z THROUGH 00Z. THEN THE TREND WILL BE TOWARD VFR THIS
EVENING AS SHOWER ACTIVITY DIMINISHES.
KPDX AND APPROACHES...MAINLY VFR IN SCATTERED SHOWERS. A BRIEF
PERIOD OF MVFR CIGS POSSIBLY LATER THIS MORNING IN ANY HEAVIER
SHOWERS...MAINLY AFTER 12Z. PREDOMINANT MVFR CONDITIONS MORE
LIKELY FROM 18Z TO 00Z AS SHOWERS BECOME STEADIER. TREND WILL BE
TOWARD VFR DURING THE LATE AFTERNOON/EVENING AS SHOWERS DIMINISH.
PYLE
&&
.MARINE...W TO NW WINDS OF 15 TO 20 KT WITH PERIODS OF GUSTS TO 25
KT TO CONTINUE THROUGH WED. THE FCST MODELS INDICATE THE STRONGEST
GRADIENT WILL BE CONFINED TO THE OUTER WATERS...WITH LESS WIND
NEAR SHORE. DECIDED TO DROP THE SMALL CRAFT ADVISORY FOR THE
INNER WATERS. WINDS WILL DECREASE LATE WED AND THE TREND WILL BE
TOWARD MORE BENIGN WEATHER LATE THIS WEEK INTO NEXT WEEKEND AS THE
UPPER LOW WEAKENS AND HIGHER SURFACE PRESSURE BUILDS INTO THE
WATERS.
INCREASED THE FCST SEAS BY A COUPLE FT THIS MORNING AS THE FCST
MODELS HAVE BEEN RUNNING A BIT TOO LOW COMPARED TO OBSERVATIONS
OVERNIGHT. EXPECT SEAS SHOULD GENERALLY HOVER IN THE 11 TO 14 FT
RANGE THROUGH WED. SEAS WILL BEGIN TO GRADUALLY SUBSIDE
THU...DROPPING BELOW 10 FT BY MIDDAY THU. SEAS WILL CONTINUE TO
GRADUALLY SUBSIDE...REACHING 5 FT OR LOWER OVER THE WEEKEND. PYLE
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT THIS AFTERNOON FOR
WATERS FROM CAPE SHOALWATER WA TO CASCADE HEAD OR FROM 10
TO 60 NM-WATERS FROM CASCADE HEAD TO FLORENCE OR FROM 10 TO
60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT THIS
AFTERNOON FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE
OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL 5 PM PDT
THIS AFTERNOON.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KSEW 220957
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
300 AM PDT WED MAY 22 2013
.SYNOPSIS...A COLD UPPER LEVEL LOW WILL GIVE SHOWERS WITH ISOLATED
AFTERNOON AND EVENING THUNDERSTORMS THROUGH THURSDAY. SNOW SHOWERS
ARE EXPECTED IN THE MOUNTAINS. THE UPPER LOW WILL WOBBLE AROUND THE
PACIFIC NORTHWEST THROUGH THE MEMORIAL DAY WEEKEND AS IT SLOWLY
FILLS AND WEAKENS. COOL TEMPERATURES THROUGH THURSDAY NIGHT WILL
GRADUALLY MODERATE OVER THE WEEKEND AND SHOWERS WILL GRADUALLY
DIMINISH STARTING THURSDAY NIGHT.
&&
.SHORT TERM...AN UPPER LEVEL LOW APPEARS TO BE CENTERED NEAR THE
DALLES OREGON EARLY THIS MORNING. RADARS SHOW SHOWERS ON THE COAST
MOVING EAST AND SOUTHEAST INTO THE AREA...SHOWERS FORMING OVER THE
NORTH INTERIOR MOVING SOUTHWARD...AND A LIGHT TO MODERATE RAIN
ROTATING AROUND A VORTICITY CENTER EAST OF YAKIMA MOVING
NORTHWESTWARD. TODAY PROMISES TO BE A SHOWERY AND COOL DAY ACROSS
WESTERN WASHINGTON. NAM12 BUFR SOUNDINGS SHOW SOME INSTABILITY THIS
AFTERNOON AND EVENING AS THE COOL AIR ALOFT WITH THE VORTICITY
CENTER TO THE SOUTHEAST MOVES INTO THE AREA. WHILE THE THREAT OF
THUNDERSTORM ACTIVITY OVER THE AREA APPEARS QUITE SMALL...THERE WERE
TSTMS WITH THE VORTICITY CENTER TO THE EAST EARLIER...SO THEY CANNOT
BE RULED OUT.
SHOWERS CONTINUE TONIGHT THEN WILL DIMINISH IN COVERAGE SOMEWHAT
THURSDAY AND THURSDAY NIGHT AS THE UPPER LOW WOBBLES BACK DOWN INTO
NORTHERN OREGON. THE AIR MASS MAY BE A BIT MORE UNSTABLE THURSDAY
AFTERNOON AND EVENING IF THERE ARE ANY BREAKS IN THE CLOUDS...SO
ISOLATED TSTMS ARE INDICATED IN THE FORECAST THU AFTN AND EVENING.
SNOW LEVELS THROUGH THU WILL BE RATHER LOW FOR THIS TIME OF YEAR IN
THE MOUNTAINS...3500-4500 FEET. BUT SNOWFALL AMOUNTS ARE EXPECTED TO
REMAIN BELOW ADVISORY CRITERIA.
THE UPPER LOW WILL ROTATE BACK UP INTO WASHINGTON ON FRIDAY...BUT IT
WILL BE IN THE PROCESS OF WEAKENING AND FILLING. EXPECT TEMPERATURES
TO BEGIN TO SLOWLY MODERATE CLOSER TOWARD NORMAL ON FRIDAY AND THE
COVERAGE OF SHOWERS TO DECREASE SOMEWHAT AND BECOME INCREASINGLY
TIED TO THE TERRAIN DURING THE AFTERNOON AND EVENING HOURS. ALBRECHT
.LONG TERM...THE UPPER LOW WILL TEND TO RETROGRADE TO JUST OFFSHORE
SATURDAY THEN SHIFT BACK INLAND SUNDAY. THIS WILL GENERALLY RESULT
IN DIURNAL MAINLY MOUNTAIN SHOWERS WITH TEMPERATURES A FEW DEGREES
BELOW NORMAL THROUGH MUCH OF THE MEMORIAL DAY WEEKEND. MEMORIAL DAY
WEATHER IS UP IN THE AIR AS ALL MODELS BRING A BRIEF WEAK SHORTWAVE
RIDGE THROUGH THE AREA SOMETIME LATE SUNDAY NIGHT OR MEMORIAL DAY
FOLLOWED BY A STRONGER FRONTAL SYSTEM ASSOCIATED WITH A DEEPER UPPER
LOW OFFSHORE BY TUESDAY. THERE IS LITTLE SKILL IN FORECASTING THESE
FEATURES SEVERAL DAYS OUT. FORECASTS SATURDAY ONWARD WERE NOT
ALTERED EARLY THIS MORNING. ALBRECHT
&&
.AVIATION...UPPER LEVEL LOW PRES WILL MEANDER OVER THE PAC NW
THROUGH THURSDAY. LOWER PRESSURE E OF THE CASCADES WILL MAINTAIN
ONSHORE FLOW OVER WRN WA. MAINLY LIGHT W TO SW FLOW ALOFT. MOIST AT
ALL LEVELS AND SOMEWHAT UNSTABLE. ISOLATED THUNDERSTORMS ARE
POSSIBLE THIS AFTERNOON AND EARLY EVENING...ROUGHLY A 15 PERCENT
CHANCE AT ANY TERMINAL. SHOWERS TODAY SHOULD INCREASE IN COVERAGE
LATER THIS AFTERNOON WITH RAIN AT TIMES TONIGHT.
CIGS VARY ACROSS THE AREA THIS MORNING WITH WRAP AROUND MOISTURE
MOVING IN FROM THE N AND E INTO THE GREATER PUGET SOUND REGION. AN
ILL DEFINED CONVERGENCE BAND ALSO APPEARS TO BE AFFECTING THE
KSEA/KBFI/KPAE TERMINALS WITH EITHER IFR OR LOW MVFR. THESE
CONDITIONS WILL CONTINUE THROUGH THE EARLY MORNING HOURS THEN CIGS
LIFTING AT MOST TERMINALS TO A LOW VFR CIG EXCEPT MVFR WITH SHOWERS.
KSEA...SSW WIND 6-10 KT...BECOMING SW 9-13 KT AFTER 18Z.
&&
.MARINE...A 1006 MB LOW NEAR THE N TIP OF VANCOUVER ISLAND WILL
WEAKEN AS IT MOVES SLOWLY S ACROSS THE WA OFFSHORE WATERS THROUGH
TONIGHT AND INTO THE OREGON OFFSHORE WATERS THU AND THU NIGHT.
A LITTLE STRONGER ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE
SATURDAY AND SUNDAY. SMALL CRAFT WINDS ARE POSSIBLE IN THE CENTRAL
AND EAST STRAIT DURING THE AFTERNOON AND NIGHT-TIME HOURS. DTM
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT FOR HAZARDOUS SEAS OUTER COASTAL WATERS.
SMALL CRAFT ADVISORY FOR ROUGH GRAYS HARBOR BAR.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KOTX 220910
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
210 AM PDT Wed May 22 2013
.SYNOPSIS...
The Inland Northwest will remain under a broad trough through at
least the middle of next week, with disturbances riding in from
the Pacific. This set up means several opportunities for
precipitation. Temperatures are expected to remain cooler than
normal through the end of this week, before some moderation.
&&
.DISCUSSION...
Today and tonight: An upper low will continue take hold of the
West with cooler than normal and occasionally wet conditions.
Early this morning the center of low was situated near Redmond,
Oregon. All guidance tracks it into the Columbia Basin by midday,
before its tracks northwest toward the Puget Sound tonight.
Meanwhile at the surface a deformation axis/trough stretched from
the ID/MT border to northeast WA is projected to edge north and
east. For today these two features will provide a high threat of
showers across the central Cascades, portions of the Wenatchee
through Moses Lake zones, and the central and northern Idaho
Panhandle and northeast Washington mountain.
A flood watch continues for parts of northeast Washington and the
northern Panhandle through this evening (06Z Thursday). The region
received some moderate rainfall amounts Tuesday. With
precipitation continuing to train across this region this morning
and more expected through the day, this will make the region
susceptible to flooding. This is especially in the hillier/steep
terrain, low spots and near smaller streams/creeks.
Elsewhere models suggest a migratory precipitation threat. As the
upper low pivots north showers are expected to expand, first over
the east third and north-central WA this morning and second toward
midday/early afternoon into the Okanogan Valley, Waterville Plateau
and northern Cascades. By tonight the low migrates into the
Cascades and eventually western Washington and the deformation
axis near the Panhandle edges northeast, while drier air comes in
from the southeast. The easterly flow will continue to provide
high precipitation chances into the Cascades and across the
northern mountains, but the threat will begin to wane as the night
progresses. The shower threat elsewhere will be dwindling as drier
air comes in.
Some instability around the center of the low, indicated by High
Level Total Totals around 30-38C and low-grade CAPE around 100-150
J/kg, will provide at least an isolated thunderstorm threat near
the Cascades through the Upper Columbia Basin, as well as in the
vicinity of the Blue Mountains.
Snow levels around the upper low are expected to be near the
3000-4000 foot mark much of the period. Snow levels elsewhere
around 5000-7000 feet (highest toward the northern Panhandle) are
expected to lower to between 4000-5000 feet through the day. Thus
some snow or at least a rain/snow mix is likely to be seen around
the Blues, the Camas Prairie and mountain passes. There is the
potential for some snow even around the higher Palouse, including
the Pullman area, this morning.
Temperatures are expected to be held much below normal under the
cool core of the upper low. This means many areas struggling to
get into the 50s today. As for overnight lows tonight into
Thursday morning, we will have to monitor reading for potential
freezing warnings. Possible locations include the Okanogan
Highlands through the northern Panhandle, as well as the Palouse.
/J. Cote`
Thursday through Tuesday...Model agreement is quite good through
Friday...with some deterioration in detail commonality after
Friday but still display reasonable agreement regarding the over
all flow regime over and near the forecast area.
Thursday through Friday the upper level closed low is firmly
planted over the forecast area. The deformation band of persistent
and frequent showers currently entering the region will be off to
the north over southern BC and Alberta by Thursday morning...but
the forecast area will be under the direct influence of the low
center cold pool aloft with minor vorticity spokes available to
gin up showers in this weakly unstable and moist air mass. This
argues for a cool and showery regime with plenty of clouds and the
possibility of some fairly weak and isolated thunderstorms.
Impossible to nail down these sub-synoptic inter-trough
disturbances at this time...but suffice it to say just about
anywhere in the forecast area will be at risk for a shower or two
each day with the best chance over the mountains ringing the basin.
The holiday weekend harbors no better news for outdoor
enthusiasts. The good news is that the stubborn upper low will
weaken and become less coherent...but the bad news is a general
troffy pattern will remain over the region through the weekend.
Both the latest GFS and ECMWF place the axis of this opening
system/trough off the coast...which implies warmer temperatures in
a pre-trough southwest flow regime. However the area will remain
under cyclonic difluent flow aloft with likely a few sub-synoptic
disturbances rounding this flow Saturday through Monday. This
overall pattern does not suggest a particularly wet period...but
the risk of showers...particularly over the northern and eastern
mountains will present itself each day. Both models hint that the
highest risk of showers associated with a stronger disturbance
will be on Sunday and focused over the southeast and Idaho
Panhandle.
Tuesday the flow becomes a bit more progressive...but also brings
the threat of a stronger wave and surface occlusion to enhance
chances of rain once again.
Overall...there is high confidence of a distinctly unsettled and
occasionally showery regime right through the next week with low
confidence in timing any periods of heightened shower activity.
Temperatures will start out below normal Thursday and gradually
achieve seasonably normal values this weekend. /Fugazzi
&&
.AVIATION...
06Z TAFS: Several bands of rain are expected over eastern Washington
and northern Idaho tonight into Wednesday. One band will remain
nearly stationary over the far NE corner of WA and Nrn ID through
Wed aftn. A second disturbance will bring -shra and isold -tsra to
the KMWH-KEAT area tonight which will linger through much of the day
Wednesday. Showers will also expand into SE WA and Lewiston area
and spread northward toward KGEG-KCOE. Overall...the air mass will
be rather moist and any breaks will lead to periods of overnight fog
or stratus until either winds incr or pcpn returns. This is a low
confidence forecast across the board for timing and reductions in
cigs for most locations. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 50 36 61 44 62 41 / 80 20 20 10 50 40
Coeur d`Alene 48 35 61 41 61 40 / 90 20 20 20 50 60
Pullman 50 34 61 40 58 40 / 70 20 20 20 60 50
Lewiston 58 39 67 46 65 46 / 50 20 20 20 60 50
Colville 54 36 66 41 69 40 / 90 60 30 20 40 50
Sandpoint 49 35 60 40 62 39 / 100 70 30 20 50 60
Kellogg 46 34 56 42 58 41 / 90 40 30 40 60 60
Moses Lake 59 40 67 45 70 44 / 50 20 30 20 30 20
Wenatchee 55 40 65 45 66 46 / 60 40 40 20 30 20
Omak 56 36 66 41 69 42 / 70 50 40 20 30 50
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Flood Watch through this evening for Northern Panhandle.
WA...Flood Watch through this evening for Northeast Mountains.
&&
$$
000
FXUS66 KOTX 220554
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1055 PM PDT Tue May 21 2013
.SYNOPSIS...
A strong cold front will sweep through the region this afternoon
into this evening with showers...a chance of thunderstorms and
breezy winds. Cool and showery weather will continue through much
of the week, but with some improvement for the holiday weekend.
&&
.DISCUSSION...
Second update for tonight: We have gone ahead and issued an areal
flood watch for the northeastern corner of WA and Northern Idaho
Panhandle. 00z guidance has come in just as wet as the 18z which
brings the moderate band of pcpn currently moving into these
locations stalls the boundary through Wednesday afternoon. This
results in good model agreement of 1-1.5" of rainfall over
northern Stevens...Pend Oreille...Boundary...and portions of
Bonner County. Some of these locations...already received 0.25" to
0.50" inches of rainfall today with thunderstorms. In addition,
snow levels remain high under this axis of moisture which will add
to runoff until snow levels lower near 4K AGL around 18z
Wednesday.
Upstream...showers and isolated thunderstorms are beginning to
expand into the southwestern Columbia Basin and Wenatchee Area.
The shortwave driving these showers will stretch with some of its
energy directed into the East Slopes and some toward southeastern
WA and the lower ID Panhandle likely to bring more rain and snow
overnight. This activity will need to be closely monitored for any
heavier showers migrating into the burn scars outside Wenatchee
but at this time...most models only bring around 0.15" with the
exception of the GFS which is closer to 0.40".
We made some changes to sky grids and pcpn chances through the
next few hours to show a break for much of the central/northern
Basin and northern East Slopes. /sb
&&
.AVIATION...
06Z TAFS: Several bands of rain are expected over eastern Washington
and northern Idaho tonight into Wednesday. One band will remain
nearly stationary over the far NE corner of WA and Nrn ID through
Wed aftn. A second disturbance will bring -shra and isold -tsra to
the KMWH-KEAT area tonight which will linger through much of the day
Wednesday. Showers will also expand into SE WA and Lewiston area
and spread northward toward KGEG-KCOE. Overall...the air mass will
be rather moist and any breaks will lead to periods of overnight fog
or stratus until either winds incr or pcpn returns. This is a low
confidence forecast across the board for timing and reductions in
cigs for most locations. /sb
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 41 51 37 61 44 61 / 20 80 20 30 10 40
Coeur d`Alene 42 48 36 61 41 60 / 100 90 30 30 20 50
Pullman 40 51 35 61 40 58 / 50 70 20 20 20 60
Lewiston 45 59 41 67 46 65 / 70 70 20 30 20 50
Colville 46 56 37 66 41 68 / 100 90 60 30 20 40
Sandpoint 45 50 37 60 40 62 / 100 100 70 40 20 40
Kellogg 42 44 35 57 42 57 / 100 90 70 30 40 60
Moses Lake 45 62 40 67 45 67 / 90 40 20 30 20 30
Wenatchee 44 57 40 65 45 65 / 90 40 30 40 20 30
Omak 44 59 36 66 41 68 / 20 80 50 40 20 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Flood Watch from 3 AM PDT Wednesday through Wednesday evening
for Northern Panhandle.
WA...Flood Watch from 3 AM PDT Wednesday through Wednesday evening
for Northeast Mountains.
&&
$$
000
FXUS66 KOTX 220506
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
1006 PM PDT Tue May 21 2013
.SYNOPSIS...
A strong cold front will sweep through the region this afternoon
into this evening with showers...a chance of thunderstorms and
breezy winds. Cool and showery weather will continue through much
of the week, but with some improvement for the holiday weekend.
&&
.DISCUSSION...
Second update for tonight: We have gone ahead and issued an areal
flood watch for the northeastern corner of WA and Northern Idaho
Panhandle. 00z guidance has come in just as wet as the 18z which
brings the moderate band of pcpn currently moving into these
locations stalls the boundary through Wednesday afternoon. This
results in good model agreement of 1-1.5" of rainfall over
northern Stevens...Pend Oreille...Boundary...and portions of
Bonner County. Some of these locations...already received 0.25" to
0.50" inches of rainfall today with thunderstorms. In addition,
snow levels remain high under this axis of moisture which will add
to runoff until snow levels lower near 4K AGL around 18z
Wednesday.
Upstream...showers and isolated thunderstorms are beginning to
expand into the southwestern Columbia Basin and Wenatchee Area.
The shortwave driving these showers will stretch with some of its
energy directed into the East Slopes and some toward southeastern
WA and the lower ID Panhandle likely to bring more rain and snow
overnight. This activity will need to be closely monitored for any
heavier showers migrating into the burn scars outside Wenatchee
but at this time...most models only bring around 0.15" with the
exception of the GFS which is closer to 0.40".
We made some changes to sky grids and pcpn chances through the
next few hours to show a break for much of the central/northern
Basin and northern East Slopes. /sb
&&
.AVIATION...
00Z TAFS: Several bands of rain are expected over eastern Washington
and northern Idaho tonight into Wednesday. The threat of
thunderstorms will dwindle quickly this evening as strong low level
cooling invades the region behind a cold front. The 18Z NAM was used
a guidance for the TAFs. It appears that a light band of rain in the
Pullman and Spokane area between 00z-03z will decay and be followed
by another more organized band of light to moderate rain after 08z.
Ceilings in the cool and wet air mass will probably fall below 2000
feet at many of the airports in the region on Wednesday morning.
Afternoon showers are expected tomorrow under the upper level cold
pool with the highest concentration over the Cascades with the
favorable southeast upslope flow. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 41 51 37 61 44 61 / 20 80 20 30 10 40
Coeur d`Alene 42 48 36 61 41 60 / 100 90 30 30 20 50
Pullman 40 51 35 61 40 58 / 50 70 20 20 20 60
Lewiston 45 59 41 67 46 65 / 70 70 20 30 20 50
Colville 46 56 37 66 41 68 / 100 90 60 30 20 40
Sandpoint 45 50 37 60 40 62 / 100 100 70 40 20 40
Kellogg 42 44 35 57 42 57 / 100 90 70 30 40 60
Moses Lake 45 62 40 67 45 67 / 90 40 20 30 20 30
Wenatchee 44 57 40 65 45 65 / 90 40 30 40 20 30
Omak 44 59 36 66 41 68 / 20 80 50 40 20 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Flood Watch from 3 AM PDT Wednesday through Wednesday evening
for Northern Panhandle.
WA...Flood Watch from 3 AM PDT Wednesday through Wednesday evening
for Northeast Mountains.
&&
$$
000
FXUS66 KSEW 220354
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
900 PM PDT PDT TUE MAY 21 2013
.SYNOPSIS...A COLD UPPER LEVEL LOW WILL MOVE INTO OREGON THIS
EVENING THEN SPIN AROUND OVER THE PACIFIC NORTHWEST THROUGH AT LEAST
FRIDAY. THE UPPER LOW WILL GIVE COOL AND SHOWERY WEATHER TO THE AREA.
&&
.SHORT TERM...AN UPPER LEVEL LOW WILL MAINTAIN A COOL SHOWERY
WEATHER PATTERN FOR THE NEXT SEVERAL DAYS. THE COOLEST AIR ALOFT
THIS EVENING IS BEING DIRECTED INTO WESTERN OREGON AND THE MAIN
CENTER OF THE LOW WILL SHIFT FROM THERE TO EASTERN OREGON BY
DAYBREAK WED. THAT AREA WILL THEN ROTATE NORTH INTO EASTERN
WASHINGTON WED AFTERNOON AND EVENING...AND THEN TO NEAR KBLI BY
DAYBREAK THU WHILE ANOTHER CENTER ROTATES ABOUT THE LOW INTO WESTERN
OREGON. SHOWERS ARE LIKELY TO BE MORE ORGANIZED IN THESE VORTICITY
CENTERS. THE AIR MASS WILL REMAIN RATHER COOL AND THE MOUNTAINS WILL
PICK UP SOME SNOW SHOWERS AT TIMES...ALTHOUGH THE HEAVIER SNOW
SHOWERS THIS EVENING ARE DOWN SOUTH IN THE OREGON CASCADES.
.LONG TERM...MODELS DIVERGE AFTER FRIDAY BUT THE HEIGHT RISES
CONTINUE. WOULD EXPECT SLOW WARMING TO CONTINUE SATURDAY THROUGH
MONDAY WITH SOME UPPER 60S IN THE FORECAST. THE GFS IS PRETTY DRY BY
MONDAY BUT THE EURO SWINGS AN UPPER TROUGH THROUGH THE AREA SUNDAY
NIGHT. HAVE KEPT THE BROAD BRUSH CHANCE POPS. ON TUESDAY A WEAK
SYSTEM ARRIVES IN BOTH MODELS...KEEPING THE CHANCE POPS GOING BUT
CHANGING THE WEATHER FROM CHANCE OF SHOWERS TO CHANCE OF RAIN. BURKE
&&
AVIATION...A DEEP UPPER TROUGH WILL REMAIN STALLED OVER THE PAC NW
THROUGH WEDNESDAY. LOWER PRESSURE E OF THE CASCADES WILL MAINTAIN
ONSHORE FLOW OVER WRN WA. LIGHT TO MODERATE W TO SW FLOW ALOFT.
MOIST AT ALL LEVELS AND SOMEWHAT UNSTABLE...ESPECIALLY WEDNESDAY.
ISOLATED THUNDERSTORMS ARE POSSIBLE WEDNESDAY AFTERNOON BUT
CONFIDENCE IS LOW. SCATTERED SHOWERS TONIGHT...THEN MORE NUMEROUS
SHOWERS WEDNESDAY AFTERNOON AND NIGHT.
LOW-END VFR TO MVFR CONDITIONS WILL CONTINUE THIS EVENING...THEN
DETERIORATE SOMEWHAT LATER TONIGHT AS LESS MIXING OCCURS.
KSEA...SW WIND 10-15 KT W/ GUSTS 22 KT...BECOMING S 5-8 KT LATER
TONIGHT AND VEERING TO SOUTHWEST AGAIN WEDNESDAY AFTERNOON. DTM
&&
.MARINE...W TO NW WINDS TO 25 KT OVER THE COASTAL WATERS WILL EASE
BELOW 20 KT AFTER MIDNIGHT AS A 1006 MB LOW FORMS OFF THE N TIP OF
VANCOUVER ISLAND. THE LOW IS EXPECTED TO WEAKEN AS IT MOVES SLOWLY S
ACROSS THE WA OFFSHORE WATERS WED AND WED NIGHT AND INTO THE OREGON
OFFSHORE WATERS THU AND THU NIGHT.
A LITTLE STRONGER ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE
SATURDAY AND SUNDAY. SMALL CRAFT WINDS CAN BE EXPECTED IN THE
CENTRAL AND EAST STRAIT DURING THE AFTERNOON AND NIGHT-TIME HOURS.
DTM
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COASTAL WATERS THROUGH MIDNIGHT...EXCEPT
FOR THE NORTHERN INNER COASTAL WATERS ZONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KPQR 220351
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
850 PM PDT TUE MAY 21 2013
.SYNOPSIS...A COLD UPPER LOW WILL REMAIN ANCHORED OVER THE
PACIFIC NW FOR THE REMAINDER OF THE WEEK...KEEPING A COOL SHOWERY
WEATHER PATTERN IN PLACE FOR THE NEXT FEW DAYS. THE LOW WILL WEAKEN
OVER THE WEEKEND...REDUCING THE CHANCES FOR SHOWERS...AND ALLOWING
TEMPS TO WARM BACK CLOSER TO NORMAL.
&&
.SHORT TERM...SATELLITE IMAGERY SHOW UPPER LEVEL LOW ANCHORED OVER
THE PACNW WITH A COUPLE SHORTWAVES PIN-WHEELING AROUND THE LOW
CENTER. THIS PATTERN WILL CONTINUE TO FAVOR HIGH POPS AND SHOWERS
WITH PERIODIC SHORT BURSTS OF LOCALLY HEAVY RAIN. LOW FREEZING
LEVELS ALSO SUPPORT SMALL HAIL POTENTIAL WITH THE SHOWERS. SNOW
LEVELS WILL REMAIN AROUND 3KFT AGAIN TOMORROW..THEN BEGIN TO RISE A
TAD THU AND AGAIN FRI GETTING UP AROUND 5KFT BY THE START OF THE
HOLIDAY WEEKEND. WEBCAMS THIS EVENING SHOWED AN INCH OR TWO OF SNOW
IN THE PASSES ALONG THE SIDE OF THE ROAD. BUFR SOUNDINGS DO SHOW SOME
INSTABILITY WED AFTERNOON/EVE IN THE WILLAMETTE VALLEY...BUT NOT
ENOUGH CONFIDENCE TO ADD THUNDER TO FCST AT THIS TIME. WILL LET MID
SHIFT FURTHER EVALUATE.
POPS DECREASE LATE WED NIGHT AND THU AS MODELS SUGGEST THE
POSSIBILITY OF DRIER AIR WORKING IN UNDER THE LOW AS THE MAIN LOW
CENTER ROTATES UP THROUGH NORTHERN WA. WHILE THE DETAILS ARE
QUESTIONABLE AT THIS POINT...WILL SHOW A LITTLE BETTER CHANCE
FOR SHOWERS AGAIN FRI AS THE UPPER LOW SWINGS BACK AROUND THROUGH
OREGON. TEMPS ARE LIKELY TO BE AT THEIR COOLEST WED WITH A DEEP
CLOUD LAYER AND ONSHORE FLOW. TW
.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS...FRIDAY EVENING
THROUGH MONDAY...SEVERAL SHORTWAVE SYSTEMS ROTATE THROUGH A BROAD
UPPER LEVEL LOW OVER THE NORTHEAST PACIFIC AND WEST COAST. THE UPPER
LOW LINGERS ACROSS THE REGION THROUGH THIS WEEK AND INTO THE
WEEKEND...KEEPING PERIODS OF SHOWERS MIXED WITH SPORADIC SUN BREAKS
IN THE FORECAST. SNOW LEVELS RISE ABOVE CASCADE PASS LEVEL AND
TEMPERATURES WARM UP CLOSER TO NORMAL TOWARD THE BEGINNING OF NEXT
WEEK...THOUGH WET AND UNSETTLED WEATHER APPEARS TO CONTINUE THROUGH
EARLY NEXT WEEK.
KWELSON
&&
.AVIATION...SCATTERED SHOWERS CONTINUE TONIGHT WITH PRIMARILY VFR
CONDITIONS WITH ONLY AN OCCASIONAL BRIEF DIP INTO THE MVFR
CATEGORY. LIFT AHEAD OF THE NEXT LOW PRESSURE DROPPING DOWN THE
COAST SHOULD PRODUCE WIDESPREAD MVFR CIGS ACROSS THE REGION LATE
TONIGHT INTO WEDNESDAY MORNING...WITH TREND TO VFR WED AFTERNOON.
KPDX AND APPROACHES...PRIMARILY VFR TONIGHT IN SHOWERS...THOUGH
TEMPORARY MVFR CONDITIONS CAN BE EXPECTED. INCREASING CHANCES FOR
MVFR CIGS AROUND 2500 FT AFTER 10Z WED...THEN BECOMING MORE LIKELY
AFTER ABOUT 15Z AS AN AREA OF LIGHT RAIN SPREADS INTO THE REGION FROM
THE WEST. /NEUMAN
&&
.MARINE...EXPECT PERIODS OF 15 TO 20 KT WINDS WITH GUSTS UP TO 30
KT...MAINLY TIED TO SHOWERS THROUGH WEDNESDAY. THERE MAY SOME
DISTINCT LULLS IN THE WINDS...PARTICULARLY BETWEEN SHOWERS AND NORTH
OF THE COLUMBIA RIVER...BUT TIMING THESE DETAILS REMAINS UNCERTAIN
ENOUGH TO NOT INCLUDE A PARTICULAR AREA. THE TREND WILL BE TOWARD
MORE BENIGN WEATHER LATE THIS WEEK INTO NEXT WEEKEND AS THE UPPER LOW
WEAKENS AND HIGHER SURFACE PRESSURE BUILDS INTO THE WATERS.
HIGHER CONFIDENCE THAT SEAS SHOULD GENERALLY HOVER IN THE 10 TO
12 FT RANGE FOR THE NEXT 24 HOURS BEFORE GRADUALLY SUBSIDING
THURSDAY THROUGH THE WEEKEND. /NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT WEDNESDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT WEDNESDAY
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT 60
NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
5 PM PDT WEDNESDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
000
FXUS66 KOTX 220242
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
742 PM PDT Tue May 21 2013
.SYNOPSIS...
A strong cold front will sweep through the region this afternoon
into this evening with showers...a chance of thunderstorms and
breezy winds. Cool and showery weather will continue through much
of the week, but with some improvement for the holiday weekend.
&&
.DISCUSSION...
Evening update: A large 540 decameter upper-level low is
currently centered off the northern Oregon Coast. The surface cold
front blew through the region this afternoon and now the trailing
midlevel cold front is slowly drifting across northeastern WA and
the ID Panhandle. A large swath of light to moderate rainfall is
accompanying the midlevel front with numerous locations receiving
upwards of 0.10 to 0.15 per hour. Dual Pol data suggest freezing
levels are dropping near 4000 feet under the heaviest
precipitation bands and are generally around 4800 ft in the
Cascades within the post frontal air mass. Lingering instability
remains along the MT/ID border and we continue to see isolated to
scattered thunderstorms which could impact locations such as
Bonners Ferry...Eastport...Clark Fork...and Prichard for the next
few hours. Models are in good agreement that the midlevel front
will continue to slowly drift north and east overnight taking the
steady pcpn with it. Upon reaching the far northeastern corner of
WA and the Idaho Panhandle...models do not indicate much movement
until perhaps late Wednesday morning and this is troublesome given
the amount of rainfall being generated over a similar area. As
such we will be closely monitoring rainfall amounts, especially
where thunderstorms moved through today for the potential of
localized flooding. At this time models produce anywhere from 0.80
to 1.50" of rain between 06z tonight and 06z Wednesday night.
We are seeing a break in the pcpn west and south of this front
with the exception of a few isolated thunderstorms in the
vicinity of Hanford, WA which will drift north toward southern
Grant and Adams County. The main pcpn threat behind the current
front will be on the next shortwave rotating within the broad low
pressure system. Cooling cloud tops can already been seen via IR
satellite imagery within the deformation axis of this wave along
the WA/OR border between Portland and Pendleton. All guidance
pivots this wave toward the E/NE overnight which will renew pcpn
chances along the southern tier of my CWA including the lower
Basin, Blue Mtns, Camas Prairie. Additional rainfall amounts up to
a quarter of an inch will be possible under this band through 12z.
&&
.AVIATION...
00Z TAFS: Several bands of rain are expected over eastern Washington
and northern Idaho tonight into Wednesday. The threat of
thunderstorms will dwindle quickly this evening as strong low level
cooling invades the region behind a cold front. The 18Z NAM was used
a guidance for the TAFs. It appears that a light band of rain in the
Pullman and Spokane area between 00z-03z will decay and be followed
by another more organized band of light to moderate rain after 08z.
Ceilings in the cool and wet air mass will probably fall below 2000
feet at many of the airports in the region on Wednesday morning.
Afternoon showers are expected tomorrow under the upper level cold
pool with the highest concentration over the Cascades with the
favorable southeast upslope flow. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 41 51 37 61 44 61 / 100 80 20 30 10 40
Coeur d`Alene 42 48 36 61 41 60 / 100 90 30 30 20 50
Pullman 40 51 35 61 40 58 / 70 70 20 20 20 60
Lewiston 45 59 41 67 46 65 / 70 70 20 30 20 50
Colville 46 56 37 66 41 68 / 100 90 60 30 20 40
Sandpoint 45 50 37 60 40 62 / 100 100 70 40 20 40
Kellogg 42 44 35 57 42 57 / 100 90 70 30 40 60
Moses Lake 45 62 40 67 45 67 / 70 40 20 30 20 30
Wenatchee 44 57 40 65 45 65 / 70 40 30 40 20 30
Omak 44 59 36 66 41 68 / 80 80 50 40 20 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
000
FXUS66 KOTX 212352
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
452 PM PDT Tue May 21 2013
.SYNOPSIS...
A strong cold front will sweep through the region this afternoon
into this evening with showers...a chance of thunderstorms and
breezy winds. Cool and showery weather will continue through much
of the week, but with some improvement for the holiday weekend.
&&
.DISCUSSION...
Tonight and Wednesday: A Big weather change is expected. A strong
cold front has moved through eastern Washington and will exit
north Idaho this evening. A band of strong thunderstorms will
march across northeast Washington and north Idaho by early this
evening with small hail and gusty winds. Meanwhile, a deformation
band of steady rain will slowly move across the Columbia Basin
into the Idaho panhandle through the night as a deep upper level
low creeps from the Washington coast inland. Wet and cool
conditions will prevail into Wednesday as the upper level low
wobbles east of the Cascades during the day. Then a secondary band
of showers develop associated with the low center, which looks
like it tracks across the Columbia basin Wednesday morning and
toward the northeast Washington mountains and Idaho panhandle by
late afternoon and early evening. Snow levels will plummet
overnight, especially across from the Cascades, to the Blue
mountains, Palouse and into Central Idaho panhandle by Wednesday
morning, with snow down to around 3k ft. The second deformation
band will lift toward the Canadian border by afternoon while snow
levels only creep up to 4k ft by afternoon. What little daytime
heating expected along with the cold air aloft will raise
instability slightly and lead to a small chance of thunderstorms
in the Cascades and Blue mountains by Wednesday afternoon.
Temperatures will be significantly cooler of 10 to 15 degrees from
today. /rfox.
Wednesday Night and Thursday: The Inland Northwest should
experience a bit of a drying trend Wednesday night into Thursday.
The large deformation band associated with a bent back frontal
occlusion is expected to migrate toward the Canadian Rockies
Wednesday night and remain well north and east of the region
through Thursday. Models have been in decent agreement the last
several runs that there should be a relative lull in precipitation
over the northern Panhandle and southeast British Columbia on
Thursday. This is good news for the swollen Kootenai and Moyie
Rivers. On Thursday, our attention will turn toward the center of
the 500mb low over western Washington and it`s upper level cold
pool. Moisture and instability profiles suggest that the best
chances for showers on Thursday will be over the Cascades and
possibly the Okanogan Highlands. The NAM and GFS both prog upwards
of 200 J/KG of surface based CAPE over the Cascades Thursday
afternoon. This won`t be a particularly moisture-rich environment
and 700-500mb flow suggests storm motion around 20 mph. However,
we will monitor any convection over the Cascades closely this year
over the burn scar areas near Wenatchee and Chelan. These scars
will have a heightened potential for mud slides.
Friday and Friday Night: The 12z models suggest that the focus for
showers will shift from the Cascades on Thursday toward northeast
Oregon and southeast Washington on Friday. The GFS and ECMWF are
in good agreement that the 500mb cold pool will drift into
northern Oregon by Friday afternoon. The highest chances for
showers looks to be in the Lewiston, Pomeroy, Winchester, Pullman
and St. Maries zones. Thunderstorms may need to be added to the
forecast (SE Washington and central/southern ID Panhandle) for
Friday afternoon if the models continue to advertise this track
and timing of the 500mb cold pool. /GKoch
Saturday through Tuesday...The Inland Northwest will continue to see
unsettled conditions through the holiday weekend. The upper low and
associated synoptic forcing will weaken so precipitation should be
more scattered in nature. Orographic ascent will become a more
significant forcing mechanism so there will be a better chance of
showers for the rising terrain north and east of the basin. With
less cloud cover and precip expected, temperatures will trend closer
to seasonal normals. /Kelch
&&
.AVIATION...
00Z TAFS: Several bands of rain are expected over eastern Washington
and northern Idaho tonight into Wednesday. The threat of
thunderstorms will dwindle quickly this evening as strong low level
cooling invades the region behind a cold front. The 18Z NAM was used
a guidance for the TAFs. It appears that a light band of rain in the
Pullman and Spokane area between 00z-03z will decay and be followed
by another more organized band of light to moderate rain after 08z.
Ceilings in the cool and wet air mass will probably fall below 2000
feet at many of the airports in the region on Wednesday morning.
Afternoon showers are expected tomorrow under the upper level cold
pool with the highest concentration over the Cascades with the
favorable southeast upslope flow. /GKoch
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 41 51 37 61 44 61 / 80 80 20 30 10 40
Coeur d`Alene 42 48 36 61 41 60 / 80 90 30 30 20 50
Pullman 40 51 35 61 40 58 / 80 70 20 20 20 60
Lewiston 45 59 41 67 46 65 / 70 70 20 30 20 50
Colville 46 56 37 66 41 68 / 90 90 60 30 20 40
Sandpoint 45 50 37 60 40 62 / 90 100 70 40 20 40
Kellogg 42 44 35 57 42 57 / 90 90 70 30 40 60
Moses Lake 45 62 40 67 45 67 / 60 40 20 30 20 30
Wenatchee 44 57 40 65 45 65 / 60 40 30 40 20 30
Omak 44 59 36 66 41 68 / 70 80 50 40 20 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
000
FXUS66 KSEW 212216
AFDSEW
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SEATTLE WA
315 PM PDT TUE MAY 21 2013
.SYNOPSIS...A COLD UPPER LEVEL LOW WILL MOVE INTO OREGON THIS
EVENING THEN SPIN AROUND OVER THE PACIFIC NORTHWEST THROUGH FRIDAY
AT LEAST. THE UPPER LOW WILL GIVE COOL AND SHOWERY WEATHER TO THE
AREA THROUGH THURSDAY. AFTER THAT TEMPERATURES WILL SLOWLY RISE AND
SHOWERS WILL DECREASE.
&&
.SHORT TERM...UPPER LEVEL LOW IS OFF THE NORTH OREGON COAST AND MOST
OF WESTERN WASHINGTON IS IN A SHOWERY PATTERN. THERE HAVE BEEN SUN
BREAKS THIS AFTERNOON AND THIS PATTERN WILL CONTINUE INTO THE
EVENING. NO THUNDERSTORMS HAVE BROKEN OUT SO REMOVED THE MINOR
MENTION OVER SOUTHERN AREAS THIS EVENING. MODELS SPIN THE UPPER LOW
AROUND OVER OREGON AND WASHINGTON OVER THE NEXT THREE DAYS SO COOL
AND SHOWERY CONDITIONS WILL REMAIN IN THE FORECAST.
ON WEDNESDAY AND THURSDAY SKIES WILL STILL BE MOSTLY CLOUDY AND
SHOWERS ARE LIKELY BUT SUN BREAKS WILL PROBABLY BE MORE NUMEROUS.
THIS COULD ALLOW A FEW THUNDERSTORMS TO DEVELOP IN THE AFTERNOONS
AND EVENINGS SO HAVE ADDED ISOLATED THUNDERSTORMS TO EACH DAY. AS IS
SO OFTEN THE CASE IN SPRING...SOME THUNDERSTORMS MAY PRODUCE SMALL
HAIL. IN FACT THERE COULD BE SOME HAIL WITHOUT THE THUNDERSTORMS.
HIGH TEMPERATURES WILL REMAIN WELL BELOW NORMAL...RISING INTO ONLY
THE LOW 60S ON THURSDAY.
ON FRIDAY THE UPPER LOW IS RIGHT OVER THE AREA BUT IT IS FILLING AND
BROADENING. THIS SHOULD DIMINISH THE SHOWERS SOMEWHAT SO POPS ARE
MOSTLY IN THE CHANCE CATEGORY. A SLOW WARMING TREND WILL CONTINUE
WITH HIGH TEMPERATURES CLIMBING A FEW DEGREES FROM THURSDAY. BURKE
.LONG TERM...MODELS DIVERGE AFTER FRIDAY BUT THE HEIGHT RISES
CONTINUE. WOULD EXPECT SLOW WARMING TO CONTINUE SATURDAY THROUGH
MONDAY WITH SOME UPPER 60S IN THE FORECAST. THE GFS IS PRETTY DRY BY
MONDAY BUT THE EURO SWINGS AN UPPER TROUGH THROUGH THE AREA SUNDAY
NIGHT. HAVE KEPT THE BROAD BRUSH CHANCE POPS. ON TUESDAY A WEAK
SYSTEM ARRIVES IN BOTH MODELS...KEEPING THE CHANCE POPS GOING BUT
CHANGING THE WEATHER FROM CHANCE OF SHOWERS TO CHANCE OF RAIN. BURKE
&&
.AVIATION...A DEEP UPPER LOW OVER THE OFFSHORE WATERS THIS AFTERNOON
WILL CONTINUE TO AFFECT THE FORECAST AREA AS IT SHIFTS SLOWLY INLAND
TONIGHT AND WEDNESDAY. THE AIR MASS WILL REMAIN MOIST AND SOMEWHAT
UNSTABLE AND SHOWERY PRECIPITATION WILL CONTINUE. ISOLATED
THUNDERSTORMS COULD DEVELOP OVER THE AREA WEDNESDAY AFTERNOON. THE
CASCADES WILL REMAIN GENERALLY OBSCURED.
LOW-END VFR TO MVFR CONDITIONS PREVAIL OVER THE FORECAST AREA THIS
AFTERNOON WITH SCATTERED SHOWERS. CLOUD COVER IS ROUGHLY SCT010
SCT-BKN030 BKN-OVC050. THESE CONDITIONS SHOULD CONTINUE GENERALLY
SPEAKING THROUGH THIS EVENING...THEN DETERIORATE SOMEWHAT TONIGHT AS
MORE SHOWERS MOVE INTO THE REGION.
KSEA...SOUTHWEST WIND 8-14 KT THIS AFTERNOON...BECOMING SOUTH
6-10 KT LATER TONIGHT AND VEERING TO SOUTHWEST AGAIN WEDNESDAY
AFTERNOON. MCDONNAL
&&
.MARINE...SMALL CRAFT ADVISORY WEST TO NORTHWEST WINDS OVER THE
COASTAL WATERS WILL EASE TONIGHT AS A 1007 MB LOW FORMS NEAR THE
NORTHWEST END OF VANCOUVER ISLAND.
THERE IS STILL LOTS OF UNCERTAINTY...AND DIFFERENCES IN MODEL
SOLUTIONS...WITH REGARD TO THE MOVEMENT OF THE LOW AND THE WINDS IT
WILL PRODUCE. MOST LIKELY IT WILL WEAKEN AS IT MOVES SLOWLY SOUTH
ACROSS THE WASHINGTON OFFSHORE WATERS WEDNESDAY AND WEDNESDAY NIGHT
AND INTO THE OREGON OFFSHORE WATERS THURSDAY AND THURSDAY NIGHT. THE
LOW COULD PRODUCE SMALL CRAFT ADVISORY WINDS OVER THE COASTAL WATERS
AND IN SOME OF THE INLAND WATERS WEDNESDAY AND WEDNESDAY NIGHT...AN
IDEA THAT IS SUPPORTED SOME OF THE UW WRF-GFS RUNS. THE FORECAST
THAT WE ARE GOING WITH FOR NOW IS A BLEND OF THAT MODEL AND THE
WEAKER NAM SOLUTION...AND THE RESULT KEEPS WINDS 20 KT OR LESS OVER
THE MARINE ZONES.
WEAK ONSHORE FLOW WILL DEVELOP FRIDAY AND CONTINUE SATURDAY AND
SUNDAY.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...NONE.
PZ...SMALL CRAFT ADVISORY COASTAL WATERS THROUGH MIDNIGHT...EXCEPT
FOR THE NORTHERN INNER COASTAL WATERS ZONE.
&&
$$
YOU CAN SEE AN ILLUSTRATED VERSION OF THE FORECAST DISCUSSION AT
WWW.WEATHER.GOV/SEATTLE/GAFD/LATEST_WEBAFD.HTML
000
FXUS66 KOTX 212138
AFDOTX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPOKANE WA
238 PM PDT Tue May 21 2013
.SYNOPSIS...
A strong cold front will sweep through the region this afternoon
into this evening with showers...a chance of thunderstorms and
breezy winds. Cool and showery weather will continue through much
of the week, but with some improvement for the holiday weekend.
&&
.DISCUSSION...
Tonight and Wednesday: A Big weather change is expected. A strong
cold front has moved through eastern Washington and will exit
north Idaho this evening. A band of strong thunderstorms will
march across northeast Washington and north Idaho by early this
evening with small hail and gusty winds. Meanwhile, a deformation
band of steady rain will slowly move across the Columbia Basin
into the Idaho panhandle through the night as a deep upper level
low creeps from the Washington coast inland. Wet and cool
conditions will prevail into Wednesday as the upper level low
wobbles east of the Cascades during the day. Then a secondary band
of showers develop associated with the low center, which looks
like it tracks across the Columbia basin Wednesday morning and
toward the northeast Washington mountains and Idaho panhandle by
late afternoon and early evening. Snow levels will plummet
overnight, especially across from the Cascades, to the Blue
mountains, Palouse and into Central Idaho panhandle by Wednesday
morning, with snow down to around 3k ft. The second deformation
band will lift toward the Canadian border by afternoon while snow
levels only creep up to 4k ft by afternoon. What little daytime
heating expected along with the cold air aloft will raise
instability slightly and lead to a small chance of thunderstorms
in the Cascades and Blue mountains by Wednesday afternoon.
Temperatures will be significantly cooler of 10 to 15 degrees from
today. /rfox.
Wednesday Night and Thursday: The Inland Northwest should
experience a bit of a drying trend Wednesday night into Thursday.
The large deformation band associated with a bent back frontal
occlusion is expected to migrate toward the Canadian Rockies
Wednesday night and remain well north and east of the region
through Thursday. Models have been in decent agreement the last
several runs that there should be a relative lull in precipitation
over the northern Panhandle and southeast British Columbia on
Thursday. This is good news for the swollen Kootenai and Moyie
Rivers. On Thursday, our attention will turn toward the center of
the 500mb low over western Washington and it`s upper level cold
pool. Moisture and instability profiles suggest that the best
chances for showers on Thursday will be over the Cascades and
possibly the Okanogan Highlands. The NAM and GFS both prog upwards
of 200 J/KG of surface based CAPE over the Cascades Thursday
afternoon. This won`t be a particularly moisture-rich environment
and 700-500mb flow suggests storm motion around 20 mph. However,
we will monitor any convection over the Cascades closely this year
over the burn scar areas near Wenatchee and Chelan. These scars
will have a heightened potential for mud slides.
Friday and Friday Night: The 12z models suggest that the focus for
showers will shift from the Cascades on Thursday toward northeast
Oregon and southeast Washington on Friday. The GFS and ECMWF are
in good agreement that the 500mb cold pool will drift into
northern Oregon by Friday afternoon. The highest chances for
showers looks to be in the Lewiston, Pomeroy, Winchester, Pullman
and St. Maries zones. Thunderstorms may need to be added to the
forecast (SE Washington and central/southern ID Panhandle) for
Friday afternoon if the models continue to advertise this track
and timing of the 500mb cold pool. /GKoch
Saturday through Tuesday...The Inland Northwest will continue to see
unsettled conditions through the holiday weekend. The upper low and
associated synoptic forcing will weaken so precipitation should be
more scattered in nature. Orographic ascent will become a more
significant forcing mechanism so there will be a better chance of
showers for the rising terrain north and east of the basin. With
less cloud cover and precip expected, temperatures will trend closer
to seasonal normals. /Kelch
&&
.AVIATION...
18Z TAFS: A cold front will sweep through the TAF sites today
lowering cigs, showers, a wind switch with gusty winds. The front
will push from KEAT to KMWH through 21z, and then march to the KGEG
vcnty, KPUW and KLWS toward 00z. Anticipate light high based showers
ahead of the front with the potential for thunderstorms. The best
chance for thunderstorms will be north and east of KGEG this
afternoon. Behind the front, expect cigs to continue to lower
overnight with steady light rain. Snow levels will drop to 4-5k ft
overnight. Cigs will be nearing MVFR by 12z. The rain will taper off
to shower by Wednesday morning. /rfox.
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 41 51 37 61 44 61 / 80 80 20 30 10 40
Coeur d`Alene 42 48 36 61 41 60 / 80 90 30 30 20 50
Pullman 40 51 35 61 40 58 / 80 70 20 20 20 60
Lewiston 45 59 41 67 46 65 / 70 70 20 30 20 50
Colville 46 56 37 66 41 68 / 90 90 60 30 20 40
Sandpoint 45 50 37 60 40 62 / 90 100 70 40 20 40
Kellogg 42 44 35 57 42 57 / 90 90 70 30 40 60
Moses Lake 45 62 40 67 45 67 / 60 40 20 30 20 30
Wenatchee 44 57 40 65 45 65 / 60 40 30 40 20 30
Omak 44 59 36 66 41 68 / 70 80 50 40 20 30
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
000
FXUS66 KPQR 212137
AFDPQR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PORTLAND OR
237 PM PDT TUE MAY 21 2013
.SYNOPSIS...A COLD UPPER LOW WILL ANCHOR ITSELF OVER THE PACIFIC NW
FOR THE REMAINDER OF THE WEEK...KEEPING A COOL SHOWERY WEATHER
PATTERN IN PLACE FOR THE NEXT FEW DAYS. THE LOW WILL WEAKEN OVER THE
WEEKEND...REDUCING THE CHANCES FOR SHOWERS...AND ALLOWING TEMPS TO
WARM BACK CLOSER TO NORMAL.
&&
.SHORT TERM...EARLY TUE AFTERNOON SATELLITE SHOWED THE MAIN TROUGH
AXIS PUSHING ONTO THE COAST. WATER VAPOR PICTURES SHOWED THE UPPER
LOW WITH TWO MAIN VORTICTY MAXIMA...ONE ROTATING INLAND OVER SW
OREGON AND THE SECOND DIGGING DOWN THE BACKSIDE OF THE LOW NEAR 46N
131W. MODELS INDICATE THE UPPER LOW IS TO REMAIN OVER THE PACIFIC NW
FOR THE NEXT FEW DAYS...WITH SHORTWAVES ROTATING AROUND THE LOW
CAUSING A DUMBELL EFFECT. INITIALLY THIS SHOULD FAVOR WIDESPREAD
SHOWERS TONIGHT THROUGH THU AS THE LARGE AREAS OF SHOWERS SEEN
OFFSHORE MOVE INLAND WITH WITH AN ONSHORE FLOW. PROBABLY DUE TO A
COOL BOUNDARY LAYER...BUFR SOUNDINGS TENDING TO NOT LOOK UNSTABLE
ENOUGH TO CARRY ANY MENTION OF THUNDER...EVEN AS THE COLDEST AIR
ALOFT MOVES ACROSS TONIGHT. WILL HOWEVER CONTINUE TO MENTION SMALL
HAIL WITH THE SHOWERS DUE TO LOW FREEZING LEVELS.
WILL TREND TOWARDS LOWER POPS LATE WED NIGHT AND THU AS MODELS
SUGGEST THE POSSIBILITY OF DRIER AIR WORKING IN UNDER THE LOW AS THE
MAIN LOW CENTER ROTATES UP THROUGH NORTHERN WA. WHILE THE DETAILS
ARE QUESTIONABLE AT THIS POINT...WILL SHOW A LITTLE BETTER CHANCE
FOR SHOWERS AGAIN FRI AS THE UPPER LOW SWINGS BACK AROUND THROUGH
OREGON. TEMPS ARE LIKELY TO BE AT THEIR COOLEST WED WITH A DEEP
CLOUD LAYER AND ONSHORE FLOW.
.LONG TERM...FRIDAY EVENING THROUGH MONDAY...SEVERAL SHORTWAVE
SYSTEMS ROTATE THROUGH A BROAD UPPER LEVEL LOW OVER THE NORTHEAST
PACIFIC AND WEST COAST. THE UPPER LOW LINGERS ACROSS THE REGION
THROUGH THIS WEEK AND INTO THE WEEKEND...KEEPING PERIODS OF SHOWERS
MIXED WITH SPORADIC SUN BREAKS IN THE FORECAST.
SNOW LEVELS RISE ABOVE CASCADE PASS LEVEL AND TEMPERATURES WARM UP
CLOSER TO NORMAL TOWARD THE BEGINNING OF NEXT WEEK...THOUGH WET AND
UNSETTLED WEATHER APPEARS TO CONTINUE THROUGH EARLY NEXT WEEK.
KWELSON
&&
.AVIATION...EXPECT A MIX OF MVFR AND VFR CONDITIONS ACROSS THE
WILLAMETTE VALLEY LATE THIS AFTERNOON AS A BAND OF STEADY RAIN
SHIFTS ACROSS THE REGION. CONDITIONS SHOULD TURN MORE SHOWERY THIS
EVENING AND BECOME GENERALLY VFR WITH ONLY AN OCCASIONAL BRIEF DIP
INTO THE MVFR CATEGORY. LIFT AHEAD OF THE NEXT LOW PRESSURE DROPPING
DOWN THE COAST SHOULD PRODUCE WIDESPREAD MVFR CIGS ACROSS THE REGION
LATE TONIGHT INTO WEDNESDAY MORNING.
KPDX AND APPROACHES...CONDITIONS SHOULD GENERALLY BE VFR THROUGH
THIS EVENING. HOWEVER...WE MAY SEE SOME TEMPORARY MVFR CONDITIONS
LATE THIS AFTERNOON AS A STEADIER BAND OF LIGHT RAIN MOVES INTO
THE AREA. CONDITIONS LOOK TO TREND MORE TOWARDS MVFR LATE TONIGHT
INTO WEDNESDAY MORNING AS AN AREA OF LIGHT RAIN SPREADS INTO THE
REGION FROM THE WEST. /NEUMAN
&&
.MARINE...EXPECT PERIODS OF 15 TO 20 KT WINDS WITH GUSTS UP TO 30
KT...MAINLY TIED TO SHOWERS THROUGH WEDNESDAY. THERE MAY SOME
DISTINCT LULLS IN THE WINDS...PARTICULARLY BETWEEN SHOWERS AND NORTH
OF THE COLUMBIA RIVER...BUT TIMING THESE DETAILS REMAINS UNCERTAIN
ENOUGH THAT WE WILL NOT GET CUTE WITH THE HEADLINES.
THE TREND WILL BE TOWARD MORE BENIGN WEATHER LATE THIS WEEK INTO
NEXT WEEKEND AS THE UPPER LOW WEAKENS AND HIGHER SURFACE PRESSURE
BUILDS INTO THE WATERS.
SEAS SHOULD GENERALLY HOVER IN THE 10 TO 12 FT RANGE FOR THE NEXT
24 HOURS BEFORE GRADUALLY SUBSIDING THURSDAY THROUGH THE WEEKEND.
/NEUMAN
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...NONE.
WA...NONE.
PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 5 PM PDT WEDNESDAY FOR
COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR OUT
60 NM.
SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 5 PM PDT WED
FOR COASTAL WATERS FROM CAPE SHOALWATER WA TO FLORENCE OR
OUT 60 NM.
SMALL CRAFT ADVISORY FOR ROUGH COLUMBIA RIVER BAR UNTIL
5 PM PDT WEDNESDAY.
&&
$$
MORE WEATHER INFORMATION ONLINE AT...
HTTP://WEATHER.GOV/PORTLAND
THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM
THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY
REFERRED TO AS THE FORECAST AREA.
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